CVE-2021-4204

Root has patched CVE-2021-4204 in the linux package for Root:Debian:11. Multiple fixed versions available.

The kernel packages contain the Linux kernel, the core of any Linux operating system.

Security Fix(es):

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Additional Changes:

For detailed information on changes in this release, see the Rocky Linux SIG Cloud 8.10 Release Notes linked from the References section.

An out-of-bounds (OOB) memory access flaw was found in the Linux kernel's eBPF due to an Improper Input Validation. This flaw allows a local attacker with a special privilege to crash the system or leak internal information.

The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high determinism requirements.

Security Fix(es):

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Additional Changes:

For detailed information on changes in this release, see the AlmaLinux Release Notes linked from the References section.

The kernel packages contain the Linux kernel, the core of any Linux operating system.

Security Fix(es):

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Additional Changes:

For detailed information on changes in this release, see the AlmaLinux Release Notes linked from the References section.

• block: Fix handling of offline queues in blk_mq_alloc_request_hctx() {CVE-2022-49720}
• drm: nv04: Fix out of bounds access {CVE-2024-27008}
• parport: Proper fix for array out-of-bounds access {CVE-2024-50074}
• drm/dp_mst: Ensure mst_primary pointer is valid in drm_dp_mst_handle_up_req() {CVE-2024-57798}
• media: uvcvideo: Fix double free in error path {CVE-2024-57980}
• vrf: use RCU protection in l3mdev_l3_out() {CVE-2025-21791}
• geneve: Fix use-after-free in geneve_find_dev(). {CVE-2025-21858}
• dm-crypt: don't modify the data when using authenticated encryption {CVE-2024-26763}
• pfifo_tail_enqueue: Drop new packet when sch->limit == 0 {CVE-2025-21702}
• iscsi_ibft: Fix UBSAN shift-out-of-bounds warning in ibft_attr_show_nic() {CVE-2025-21993}
• vlan: enforce underlying device type {CVE-2025-21920}
• Bluetooth: L2CAP: Fix slab-use-after-free Read in l2cap_send_cmd {CVE-2025-21969}
• HID: intel-ish-hid: Fix use-after-free issue in ishtp_hid_remove() {CVE-2025-21928}
• ALSA: usb-audio: Fix potential out-of-bound accesses for Extigy and Mbox devices {CVE-2024-53197}
• can: bcm: Fix UAF in bcm_proc_show() {CVE-2023-52922}
• bpf: Fix out of bounds access for ringbuf helpers {CVE-2021-4204}
• bpf: Generally fix helper register offset check {CVE-2021-4204}
• bpf: Generalize check_ctx_reg for reuse with other types {CVE-2021-4204}
• bpf: Make context access check generic {CVE-2021-4204}
• gso: do not skip outer ip header in case of ipip and net_failover {CVE-2022-48936}
• ALSA: usb-audio: Fix an out-of-bounds bug in __snd_usb_parse_audio_interface() {CVE-2022-48701}
• ALSA: emu10k1: Fix out of bounds access in snd_emu10k1_pcm_channel_alloc() {CVE-2022-48702}

• drm/dp_mst: Ensure mst_primary pointer is valid in drm_dp_mst_handle_up_req() {CVE-2024-57798}
• block: Fix handling of offline queues in blk_mq_alloc_request_hctx() {CVE-2022-49720}
• drm: nv04: Fix out of bounds access {CVE-2024-27008}
• parport: Proper fix for array out-of-bounds access {CVE-2024-50074}
• Bluetooth: L2CAP: Fix slab-use-after-free Read in l2cap_send_cmd {CVE-2025-21969}
• media: uvcvideo: Fix double free in error path {CVE-2024-57980}
• vrf: use RCU protection in l3mdev_l3_out() {CVE-2025-21791}
• geneve: Fix use-after-free in geneve_find_dev(). {CVE-2025-21858}
• dm-crypt: don't modify the data when using authenticated encryption {CVE-2024-26763}
• pfifo_tail_enqueue: Drop new packet when sch->limit == 0 {CVE-2025-21702}
• iscsi_ibft: Fix UBSAN shift-out-of-bounds warning in ibft_attr_show_nic() {CVE-2025-21993}
• vlan: enforce underlying device type {CVE-2025-21920}
• HID: intel-ish-hid: Fix use-after-free issue in ishtp_hid_remove() {CVE-2025-21928}
• ALSA: usb-audio: Fix potential out-of-bound accesses for Extigy and Mbox devices {CVE-2024-53197}
• can: bcm: Fix UAF in bcm_proc_show() {CVE-2023-52922}
• gso: do not skip outer ip header in case of ipip and net_failover {CVE-2022-48936}
• cifs: fix potential double free during failed mount {CVE-2022-49541}
• bpf: Fix out of bounds access for ringbuf helpers {CVE-2021-4204}
• bpf: Generally fix helper register offset check {CVE-2021-4204}
• bpf: Generalize check_ctx_reg for reuse with other types {CVE-2021-4204}
• ALSA: usb-audio: Fix an out-of-bounds bug in __snd_usb_parse_audio_interface() {CVE-2022-48701}
• ALSA: emu10k1: Fix out of bounds access in snd_emu10k1_pcm_channel_alloc() {CVE-2022-48702}

This kernel update is based on upstream 5.15.15 and fixes at least the following security issues:

A data leak flaw was found in the way XFS_IOC_ALLOCSP IOCTL in the XFS filesystem allowed for size increase of files with unaligned size. A local attacker could use this flaw to leak data on the XFS filesystem otherwise not accessible to them (CVE-2021-4155).

An unprivileged write to the file handler flaw in the Linux kernel's control groups and namespaces subsystem was found in the way users have access to some less privileged process that are controlled by cgroups and have higher privileged parent process. It is actually both for cgroup2 and cgroup1 versions of control groups. A local user could use this flaw to crash the system or escalate their privileges on the system (CVE-2021-4197).

Lack of proper validation of user-supplied eBPF programs prior to executing them. An attacker can leverage this vulnerability to escalate privileges and execute code in the context of the kernel (CVE-2021-4204).

A use-after-free exists in drivers/tee/tee_shm.c in the TEE subsystem in the Linux kernel through 5.15.11. This occurs because of a race condition in tee_shm_get_from_id during an attempt to free a shared memory object (CVE-2021-44733).

pep_sock_accept in net/phonet/pep.c in the Linux kernel through 5.15.8 has a refcount leak (CVE-2021-45095).

The ksmbd server through 3.4.2, as used in the Linux kernel through 5.15.8, sometimes communicates in cleartext even though encryption has been enabled. This occurs because it sets the SMB2_GLOBAL_CAP_ENCRYPTION flag when using the SMB 3.1.1 protocol, which is a violation of the SMB protocol specification. When Windows 10 detects this protocol violation, it disables encryption (CVE-2021-45100).

kernel/bpf/verifier.c in the Linux kernel through 5.15.14 allows local users to gain privileges because of the availability of pointer arithmetic via certain *_OR_NULL pointer types (CVE-2022-23222).

In addition to the upstream changes, we also have changed the following:

• iwlwifi: mvm: check if SAR GEO is supported before sending command
• select: Fix indefinitely sleeping task in poll_schedule_timeout()
• ALSA: hda: Add AlderLake-N/P PCI ID
• enable NF_TABLES_INET, NFT_REJECT_INET and NFT_FIB_INET (mga#29852)
• disable CIFS_SMB_DIRECT on desktop kernels as it makes loading cifs deps fail on some setups (mga#29784)
• disable unprivileged bpf by default to mitigate other potential security issues with bpf

For other upstream fixes, see the referenced changelogs.

The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high determinism requirements.

Security Fix(es):

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Additional Changes:

For detailed information on changes in this release, see the Rocky Linux 8.10 Release Notes linked from the References section.

The kernel packages contain the Linux kernel, the core of any Linux operating system.

Security Fix(es):

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Additional Changes:

For detailed information on changes in this release, see the Rocky Linux 8.10 Release Notes linked from the References section.

The SUSE Linux Enterprise 15 SP4 kernel was updated.

The following security bugs were fixed:

• CVE-2022-29900, CVE-2022-29901: Fixed the RETBLEED attack, a new Spectre like Branch Target Buffer attack, that can leak arbitrary kernel information (bsc#1199657).
• CVE-2022-34918: Fixed a buffer overflow with nft_set_elem_init() that could be used by a local attacker to escalate privileges (bnc#1201171).
• CVE-2021-26341: Some AMD CPUs may transiently execute beyond unconditional direct branches, which may potentially result in data leakage (bsc#1201050).
• CVE-2022-20154: Fixed a use after free due to a race condition in lock_sock_nested of sock.c. This could lead to local escalation of privilege with System execution privileges needed (bsc#1200599).
• CVE-2022-2318: Fixed a use-after-free vulnerabilities in the timer handler in net/rose/rose_timer.c that allow attackers to crash the system without any privileges (bsc#1201251).
• CVE-2022-1462: Fixed an out-of-bounds read flaw in the TeleTYpe subsystem (bnc#1198829).
• CVE-2022-26365, CVE-2022-33740, CVE-2022-33741, CVE-2022-33742: Fixed multiple potential data leaks with Block and Network devices when using untrusted backends (bsc#1200762).
• CVE-2022-33743: Fixed a Denial of Service related to XDP (bsc#1200763).
• CVE-2022-1679: Fixed a use-after-free in the Atheros wireless driver in the way a user forces the ath9k_htc_wait_for_target function to fail with some input messages (bnc#1199487).
• CVE-2022-20132: Fixed out of bounds read due to improper input validation in lg_probe and related functions of hid-lg.c (bnc#1200619).
• CVE-2022-33981: Fixed use-after-free in floppy driver (bsc#1200692)
• CVE-2022-1012: Fixed information leak caused by small table perturb size in the TCP source port generation algorithm (bsc#1199482).
• CVE-2022-1998: Fixed a use after free in the file system notify functionality (bnc#1200284).
• CVE-2022-1966: Fixed a use-after-free vulnerability in the Netfilter subsystem. This flaw allowed a local attacker with user access to cause a privilege escalation issue. (bnc#1200015)
• CVE-2022-1852: Fixed a null-ptr-deref in the kvm module which can lead to DoS. (bsc#1199875)
• CVE-2022-1789: Fixed a NULL pointer dereference when shadow paging is enabled. (bnc#1199674)
• CVE-2022-1508: Fixed an out-of-bounds read flaw that could cause the system to crash. (bsc#1198968)
• CVE-2022-1671: Fixed a null-ptr-deref bugs in net/rxrpc/server_key.c, unprivileged users could easily trigger it via ioctl. (bsc#1199439)
• CVE-2022-1651: Fixed a bug in ACRN Device Model emulates virtual NICs in VM. This flaw may allow a local privileged attacker to leak kernel unauthorized information and also cause a denial of service problem. (bsc#1199433)
• CVE-2022-29582: Fixed a use-after-free due to a race condition in io_uring timeouts. This can be triggered by a local user who has no access to any user namespace; however, the race condition perhaps can only be exploited infrequently. (bnc#1198811)
• CVE-2022-0494: Fixed a kernel information leak flaw in the scsi_ioctl function. This flaw allowed a local attacker with a special user privilege to create issues with confidentiality. (bnc#1197386)
• CVE-2021-4204: Fixed a vulnerability that allows local attackers to escalate privileges on affected installations via ebpf. (bnc#1194111)
• CVE-2022-23222: Fixed a bug that allowed local users to gain privileges. (bnc#1194765)
• CVE-2022-0264: Fixed a vulnerability in the Linux kernel's eBPF verifier when handling internal data structures. Internal memory locations could be returned to userspace. A local attacker with the permissions to insert eBPF code to the kernel can use this to leak internal kernel memory details defeating some of the exploit mitigations in place for the kernel. (bnc#1194826)
• CVE-2022-1016: Fixed a vulnerability in the nf_tables component of the netfilter subsystem. This vulnerability gives an attacker a powerful primitive that can be used to both read from and…

The SUSE Linux Enterprise 15 SP4 kernel was updated.

The following security bugs were fixed:

• CVE-2022-29900, CVE-2022-29901: Fixed the RETBLEED attack, a new Spectre like Branch Target Buffer attack, that can leak arbitrary kernel information (bsc#1199657).
• CVE-2022-34918: Fixed a buffer overflow with nft_set_elem_init() that could be used by a local attacker to escalate privileges (bnc#1201171).
• CVE-2021-26341: Some AMD CPUs may transiently execute beyond unconditional direct branches, which may potentially result in data leakage (bsc#1201050).
• CVE-2022-20154: Fixed a use after free due to a race condition in lock_sock_nested of sock.c. This could lead to local escalation of privilege with System execution privileges needed (bsc#1200599).
• CVE-2022-2318: Fixed a use-after-free vulnerabilities in the timer handler in net/rose/rose_timer.c that allow attackers to crash the system without any privileges (bsc#1201251).
• CVE-2022-26365, CVE-2022-33740, CVE-2022-33741, CVE-2022-33742: Fixed multiple potential data leaks with Block and Network devices when using untrusted backends (bsc#1200762).
• CVE-2022-33743: Fixed a Denial of Service related to XDP (bsc#1200763).
• CVE-2022-1966: Fixed a use-after-free vulnerability in the Netfilter subsystem. This flaw allowed a local attacker with user access to cause a privilege escalation issue. (bnc#1200015)
• CVE-2022-1852: Fixed a null-ptr-deref in the kvm module which can lead to DoS. (bsc#1199875)
• CVE-2022-1789: Fixed a NULL pointer dereference when shadow paging is enabled. (bnc#1199674)
• CVE-2022-1508: Fixed an out-of-bounds read flaw that could cause the system to crash. (bsc#1198968)
• CVE-2022-1671: Fixed a null-ptr-deref bugs in net/rxrpc/server_key.c, unprivileged users could easily trigger it via ioctl. (bsc#1199439)
• CVE-2022-1651: Fixed a bug in ACRN Device Model emulates virtual NICs in VM. This flaw may allow a local privileged attacker to leak kernel unauthorized information and also cause a denial of service problem. (bsc#1199433)
• CVE-2022-29582: Fixed a use-after-free due to a race condition in io_uring timeouts. This can be triggered by a local user who has no access to any user namespace; however, the race condition perhaps can only be exploited infrequently. (bnc#1198811)
• CVE-2022-0494: Fixed a kernel information leak flaw in the scsi_ioctl function. This flaw allowed a local attacker with a special user privilege to create issues with confidentiality. (bnc#1197386)
• CVE-2021-4204: Fixed a vulnerability that allows local attackers to escalate privileges on affected installations via ebpf. (bnc#1194111)
• CVE-2022-23222: Fixed a bug that allowed local users to gain privileges. (bnc#1194765)
• CVE-2022-0264: Fixed a vulnerability in the Linux kernel's eBPF verifier when handling internal data structures. Internal memory locations could be returned to userspace. A local attacker with the permissions to insert eBPF code to the kernel can use this to leak internal kernel memory details defeating some of the exploit mitigations in place for the kernel. (bnc#1194826)
• CVE-2022-1016: Fixed a vulnerability in the nf_tables component of the netfilter subsystem. This vulnerability gives an attacker a powerful primitive that can be used to both read from and write to relative stack data, which can lead to arbitrary code execution. (bsc#1197227)
• CVE-2022-1205: Fixed null pointer dereference and use-after-free vulnerabilities that allow an attacker to crash the linux kernel by simulating Amateur Radio. (bsc#1198027)
• CVE-2022-1198: Fixed an use-after-free vulnerability that allow an attacker to crash the linux kernel by simulating Amateur Radio (bsc#1198030).
• CVE-2022-1972: Fixed a buffer overflow in nftable that could lead to privilege escalation. (bsc#1200019)
• CVE-2022-21127: Fixed a stale MMIO data transient which can be exploited to speculatively/transiently disclose information via spectre like attacks. (bsc#1199650)
• CVE-2022-21123: Fixed a…

The SUSE Linux Enterprise 15 SP5 kernel was updated to receive various security bugfixes.

The following security bugs were fixed:

• CVE-2024-44947: Initialize beyond-EOF page contents before setting uptodate (bsc#1229454).
• CVE-2024-36936: Touch soft lockup during memory accept (bsc#1225773).
• CVE-2022-48706: Do proper cleanup if IFCVF init fails (bsc#1225524).
• CVE-2024-43883: Do not drop references before new references are gained (bsc#1229707).
• CVE-2024-41062: Sync sock recv cb and release (bsc#1228576).
• CVE-2024-43861: Fix memory leak for not ip packets (bsc#1229500).
• CVE-2024-36270: Fix reference in patches.suse/netfilter-tproxy-bail-out-if-IP-has-been-disabled-on.patch (bsc#1226798)
• CVE-2023-52489: Fix race in accessing memory_section->usage (bsc#1221326).
• CVE-2024-43893: Check uartclk for zero to avoid divide by zero (bsc#1229759).
• CVE-2024-43821: Fix a possible null pointer dereference (bsc#1229315).
• CVE-2024-43900: Avoid use-after-free in load_firmware_cb() (bsc#1229756).
• CVE-2024-44938: Fix shift-out-of-bounds in dbDiscardAG (bsc#1229792).
• CVE-2024-44939: Fix null ptr deref in dtInsertEntry (bsc#1229820).
• CVE-2024-41087: Fix double free on error (CVE-2024-41087,bsc#1228466).
• CVE-2024-42277: Avoid NULL deref in sprd_iommu_hw_en (bsc#1229409).
• CVE-2024-43902: Add null checker before passing variables (bsc#1229767).
• CVE-2024-43904: Add null checks for 'stream' and 'plane' before dereferencing (bsc#1229768)
• CVE-2024-43880: Put back removed metod in struct objagg_ops (bsc#1229481).
• CVE-2024-43884: Add error handling to pair_device() (bsc#1229739)
• CVE-2024-43899: Fix null pointer deref in dcn20_resource.c (bsc#1229754).
• CVE-2022-48920: Get rid of warning on transaction commit when using flushoncommit (bsc#1229658).
• CVE-2023-52906: Fix warning during failed attribute validation (bsc#1229527).
• CVE-2024-43882: Fixed ToCToU between perm check and set-uid/gid usage. (bsc#1229503)
• CVE-2024-43866: Always drain health in shutdown callback (bsc#1229495).
• CVE-2024-26812: Struct virqfd kABI workaround (bsc#1222808).
• CVE-2022-48912: Fix use-after-free in __nf_register_net_hook() (bsc#1229641)
• CVE-2024-27010: Fix mirred deadlock on device recursion (bsc#1223720).
• CVE-2022-48906: Correctly set DATA_FIN timeout when number of retransmits is large (bsc#1229605)
• CVE-2024-42155: Wipe copies of protected- and secure-keys (bsc#1228733).
• CVE-2024-42156: Wipe copies of clear-key structures on failure (bsc#1228722).
• CVE-2023-52899: Add exception protection processing for vd in axi_chan_handle_err function (bsc#1229569).
• CVE-2024-42158: Use kfree_sensitive() to fix Coccinelle warnings (bsc#1228720).
• CVE-2024-26631: Fix data-race in ipv6_mc_down / mld_ifc_work (bsc#1221630).
• CVE-2024-43873: Always initialize seqpacket_allow (bsc#1229488)
• CVE-2024-40905: Fix possible race in __fib6_drop_pcpu_from() (bsc#1227761)
• CVE-2024-39489: Fix memleak in seg6_hmac_init_algo (bsc#1227623)
• CVE-2021-47106: Fix use-after-free in nft_set_catchall_destroy() (bsc#1220962)
• CVE-2021-47517: Fix panic when interrupt coaleceing is set via ethtool (bsc#1225428).
• CVE-2024-36489: Fix missing memory barrier in tls_init (bsc#1226874)
• CVE-2024-41020: Fix fcntl/close race recovery compat path (bsc#1228427).
• CVE-2024-27079: Fix NULL domain on device release (bsc#1223742).
• CVE-2024-35897: Discard table flag update with pending basechain deletion (bsc#1224510).
• CVE-2024-27403: Restore const specifier in flow_offload_route_init() (bsc#1224415).
• CVE-2024-27011: Fix memleak in map from abort path (bsc#1223803).
• CVE-2024-43819: Reject memory region operations for ucontrol VMs (bsc#1229290 git-fixes).
• CVE-2024-26668: Reject configurations that cause integer overflow (bsc#1222335).
• CVE-2024-26835: Set dormant flag on hook register failure (bsc#1222967).
• CVE-2024-26808: Handle NETDEV_UNREGISTER for inet/ingress basechain (bsc#1222634).
• CVE-2024-27016: Validate pppoe header (bsc#1223807). -…

It was discovered that the NFS server implementation in the Linux kernel contained an out-of-bounds write vulnerability. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-4090)

It was discovered that the eBPF implementation in the Linux kernel did not properly validate the memory size of certain ring buffer operation arguments. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-4204)

Nadav Amit discovered that the hugetlb implementation in the Linux kernel did not perform TLB flushes under certain conditions. A local attacker could use this to leak or alter data from other processes that use huge pages. (CVE-2021-4002)

It was discovered that the eBPF implementation in the Linux kernel did not properly validate the memory size of certain ring buffer operation arguments. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-4204)

It was discovered that a race condition existed in the overlay file system implementation in the Linux kernel. A local attacker could use this to cause a denial of service (system crash). (CVE-2021-20321)

It was discovered that the NFC subsystem in the Linux kernel contained a use-after-free vulnerability in its NFC Controller Interface (NCI) implementation. A local attacker could possibly use this to cause a denial of service (system crash) or execute arbitrary code. (CVE-2021-3760)

It was discovered that an integer overflow could be triggered in the eBPF implementation in the Linux kernel when preallocating objects for stack maps. A privileged local attacker could use this to cause a denial of service or possibly execute arbitrary code. (CVE-2021-41864)

It was discovered that the KVM implementation for POWER8 processors in the Linux kernel did not properly keep track if a wakeup event could be resolved by a guest. An attacker in a guest VM could possibly use this to cause a denial of service (host OS crash). (CVE-2021-43056)

It was discovered that the TIPC Protocol implementation in the Linux kernel did not properly validate MSG_CRYPTO messages in some situations. An attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code. (CVE-2021-43267)

It was discovered that the ISDN CAPI implementation in the Linux kernel contained a race condition in certain situations that could trigger an array out-of-bounds bug. A privileged local attacker could possibly use this to cause a denial of service or execute arbitrary code. (CVE-2021-43389)

It was discovered that the eBPF implementation in the Linux kernel did not properly validate the memory size of certain ring buffer operation arguments. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code.