CVE-2023-28642

runc is a CLI tool for spawning and running containers according to the OCI specification. It was found that AppArmor can be bypassed when /proc inside the container is symlinked with a specific mount configuration. This issue has been fixed in runc version 1.1.5, by prohibiting symlinked /proc. See PR #3785 for details. users are advised to upgrade. Users unable to upgrade should avoid using an untrusted container image.

runc is a CLI tool for spawning and running containers according to the OCI specification. It was found that AppArmor can be bypassed when /proc inside the container is symlinked with a specific mount configuration. This issue has been fixed in runc version 1.1.5, by prohibiting symlinked /proc. See PR #3785 for details. users are advised to upgrade. Users unable to upgrade should avoid using an untrusted container image.

Impact

It was found that AppArmor, and potentially SELinux, can be bypassed when /proc inside the container is symlinked with a specific mount configuration.

Patches

Fixed in runc v1.1.5, by prohibiting symlinked /proc: https://github.com/opencontainers/runc/pull/3785

This PR fixes CVE-2023-27561 as well.

Workarounds

Avoid using an untrusted container image.

runc is a CLI tool for spawning and running containers according to the OCI specification.

Security Fix(es):

runc is a CLI tool for spawning and running containers according to the OCI specification. In affected versions it was found that rootless runc makes /sys/fs/cgroup writable in following conditons: 1. when runc is executed inside the user namespace, and the config.json does not specify the cgroup namespace to be unshared (e.g.., (docker|podman|nerdctl) run --cgroupns=host, with Rootless Docker/Podman/nerdctl) or 2. when runc is executed outside the user namespace, and /sys is mounted with rbind, ro (e.g., runc spec --rootless; this condition is very rare). A container may gain the write access to user-owned cgroup hierarchy /sys/fs/cgroup/user.slice/... on the host . Other users's cgroup hierarchies are not affected. Users are advised to upgrade to version 1.1.5. Users unable to upgrade may unshare the cgroup namespace ((docker|podman|nerdctl) run --cgroupns=private). This is the default behavior of Docker/Podman/nerdctl on cgroup v2 hosts. or add /sys/fs/cgroup to maskedPaths.(CVE-2023-25809)

runc is a CLI tool for spawning and running containers according to the OCI specification. It was found that AppArmor can be bypassed when /proc inside the container is symlinked with a specific mount configuration. This issue has been fixed in runc version 1.1.5, by prohibiting symlinked /proc. See PR #3785 for details. users are advised to upgrade. Users unable to upgrade should avoid using an untrusted container image.(CVE-2023-28642)

runc is a CLI tool for spawning and running containers according to the OCI specification.

Security Fix(es):

runc is a CLI tool for spawning and running containers according to the OCI specification. It was found that AppArmor can be bypassed when /proc inside the container is symlinked with a specific mount configuration. This issue has been fixed in runc version 1.1.5, by prohibiting symlinked /proc. See PR #3785 for details. users are advised to upgrade. Users unable to upgrade should avoid using an untrusted container image.(CVE-2023-28642)

runc is a CLI tool for spawning and running containers according to the OCI specification.

Security Fix(es):

runc is a CLI tool for spawning and running containers according to the OCI specification. It was found that AppArmor can be bypassed when /proc inside the container is symlinked with a specific mount configuration. This issue has been fixed in runc version 1.1.5, by prohibiting symlinked /proc. See PR #3785 for details. users are advised to upgrade. Users unable to upgrade should avoid using an untrusted container image.(CVE-2023-28642)

runc is a CLI tool for spawning and running containers according to the OCI specification.

Security Fix(es):

runc is a CLI tool for spawning and running containers according to the OCI specification. It was found that AppArmor can be bypassed when /proc inside the container is symlinked with a specific mount configuration. This issue has been fixed in runc version 1.1.5, by prohibiting symlinked /proc. See PR #3785 for details. users are advised to upgrade. Users unable to upgrade should avoid using an untrusted container image.(CVE-2023-28642)

The container-tools module contains tools for working with containers, notably podman, buildah, skopeo, and runc.

Security Fix(es):

• go-yaml: Improve heuristics preventing CPU/memory abuse by parsing malicious or large YAML documents (CVE-2022-3064)

• golang: html/template: improper handling of JavaScript whitespace (CVE-2023-24540)

• net/http, golang.org/x/net/http2: avoid quadratic complexity in HPACK decoding (CVE-2022-41723)

• golang: crypto/tls: large handshake records may cause panics (CVE-2022-41724)

• golang: net/http, mime/multipart: denial of service from excessive resource consumption (CVE-2022-41725)

• golang.org/x/net/html: Cross site scripting (CVE-2023-3978)

• golang: net/http, net/textproto: denial of service from excessive memory allocation (CVE-2023-24534)

• golang: net/http, net/textproto, mime/multipart: denial of service from excessive resource consumption (CVE-2023-24536)

• golang: go/parser: Infinite loop in parsing (CVE-2023-24537)

• golang: html/template: backticks not treated as string delimiters (CVE-2023-24538)

• golang: html/template: improper sanitization of CSS values (CVE-2023-24539)

• runc: Rootless runc makes /sys/fs/cgroup writable (CVE-2023-25809)

• runc: volume mount race condition (regression of CVE-2019-19921) (CVE-2023-27561)

• runc: AppArmor can be bypassed when /proc inside the container is symlinked with a specific mount configuration (CVE-2023-28642)

• golang: html/template: improper handling of empty HTML attributes (CVE-2023-29400)

• golang: net/http: insufficient sanitization of Host header (CVE-2023-29406)

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 8.9 Release Notes linked from the References section.

The container-tools module contains tools for working with containers, notably podman, buildah, skopeo, and runc.

Security Fix(es):

• go-yaml: Improve heuristics preventing CPU/memory abuse by parsing malicious or large YAML documents (CVE-2022-3064)

• golang: html/template: improper handling of JavaScript whitespace (CVE-2023-24540)

• net/http, golang.org/x/net/http2: avoid quadratic complexity in HPACK decoding (CVE-2022-41723)

• golang: crypto/tls: large handshake records may cause panics (CVE-2022-41724)

• golang: net/http, mime/multipart: denial of service from excessive resource consumption (CVE-2022-41725)

• golang.org/x/net/html: Cross site scripting (CVE-2023-3978)

• golang: net/http, net/textproto: denial of service from excessive memory allocation (CVE-2023-24534)

• golang: net/http, net/textproto, mime/multipart: denial of service from excessive resource consumption (CVE-2023-24536)

• golang: go/parser: Infinite loop in parsing (CVE-2023-24537)

• golang: html/template: backticks not treated as string delimiters (CVE-2023-24538)

• golang: html/template: improper sanitization of CSS values (CVE-2023-24539)

• containerd: Supplementary groups are not set up properly (CVE-2023-25173)

• runc: Rootless runc makes /sys/fs/cgroup writable (CVE-2023-25809)

• runc: volume mount race condition (regression of CVE-2019-19921) (CVE-2023-27561)

• runc: AppArmor can be bypassed when /proc inside the container is symlinked with a specific mount configuration (CVE-2023-28642)

• golang: html/template: improper handling of empty HTML attributes (CVE-2023-29400)

• golang: net/http: insufficient sanitization of Host header (CVE-2023-29406)

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 8.9 Release Notes linked from the References section.

runc is a CLI tool for spawning and running containers according to the OCI specification. It was found that AppArmor can be bypassed when /proc inside the container is symlinked with a specific mount configuration. This issue has been fixed in runc version 1.1.5, by prohibiting symlinked /proc. See PR #3785 for details. users are advised to upgrade. Users unable to upgrade should avoid using an untrusted container image.

The runC tool is a lightweight, portable implementation of the Open Container Format (OCF) that provides container runtime.

Security Fix(es):

• golang: crypto/tls: large handshake records may cause panics (CVE-2022-41724)
• runc: Rootless runc makes /sys/fs/cgroup writable (CVE-2023-25809)
• runc: volume mount race condition (regression of CVE-2019-19921) (CVE-2023-27561)
• runc: AppArmor can be bypassed when /proc inside the container is symlinked with a specific mount configuration (CVE-2023-28642)
• runc: integer overflow in netlink bytemsg length field allows attacker to override netlink-based container configuration (CVE-2021-43784)

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 container-tools module contains tools for working with containers, notably podman, buildah, skopeo, and runc.

Security Fix(es):

• go-yaml: Improve heuristics preventing CPU/memory abuse by parsing malicious or large YAML documents (CVE-2022-3064)
• golang: html/template: improper handling of JavaScript whitespace (CVE-2023-24540)
• net/http, golang.org/x/net/http2: avoid quadratic complexity in HPACK decoding (CVE-2022-41723)
• golang: crypto/tls: large handshake records may cause panics (CVE-2022-41724)
• golang: net/http, mime/multipart: denial of service from excessive resource consumption (CVE-2022-41725)
• golang.org/x/net/html: Cross site scripting (CVE-2023-3978)
• golang: net/http, net/textproto: denial of service from excessive memory allocation (CVE-2023-24534)
• golang: net/http, net/textproto, mime/multipart: denial of service from excessive resource consumption (CVE-2023-24536)
• golang: go/parser: Infinite loop in parsing (CVE-2023-24537)
• golang: html/template: backticks not treated as string delimiters (CVE-2023-24538)
• golang: html/template: improper sanitization of CSS values (CVE-2023-24539)
• runc: Rootless runc makes /sys/fs/cgroup writable (CVE-2023-25809)
• runc: volume mount race condition (regression of CVE-2019-19921) (CVE-2023-27561)
• runc: AppArmor can be bypassed when /proc inside the container is symlinked with a specific mount configuration (CVE-2023-28642)
• golang: html/template: improper handling of empty HTML attributes (CVE-2023-29400)
• golang: net/http: insufficient sanitization of Host header (CVE-2023-29406)

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 container-tools module contains tools for working with containers, notably podman, buildah, skopeo, and runc.

Security Fix(es):

• go-yaml: Improve heuristics preventing CPU/memory abuse by parsing malicious or large YAML documents (CVE-2022-3064)
• golang: html/template: improper handling of JavaScript whitespace (CVE-2023-24540)
• net/http, golang.org/x/net/http2: avoid quadratic complexity in HPACK decoding (CVE-2022-41723)
• golang: crypto/tls: large handshake records may cause panics (CVE-2022-41724)
• golang: net/http, mime/multipart: denial of service from excessive resource consumption (CVE-2022-41725)
• golang.org/x/net/html: Cross site scripting (CVE-2023-3978)
• golang: net/http, net/textproto: denial of service from excessive memory allocation (CVE-2023-24534)
• golang: net/http, net/textproto, mime/multipart: denial of service from excessive resource consumption (CVE-2023-24536)
• golang: go/parser: Infinite loop in parsing (CVE-2023-24537)
• golang: html/template: backticks not treated as string delimiters (CVE-2023-24538)
• golang: html/template: improper sanitization of CSS values (CVE-2023-24539)
• containerd: Supplementary groups are not set up properly (CVE-2023-25173)
• runc: Rootless runc makes /sys/fs/cgroup writable (CVE-2023-25809)
• runc: volume mount race condition (regression of CVE-2019-19921) (CVE-2023-27561)
• runc: AppArmor can be bypassed when /proc inside the container is symlinked with a specific mount configuration (CVE-2023-28642)
• golang: html/template: improper handling of empty HTML attributes (CVE-2023-29400)
• golang: net/http: insufficient sanitization of Host header (CVE-2023-29406)

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.

• upgrade to runc 1.2.8 to fix multiple critical security vulnerabilities:
• CVE-2024-21626: fix file descriptor leak vulnerability allowing container escape
• CVE-2025-52565: fix container escape with malicious config due to /dev/console mount races
• CVE-2025-31133: fix container escape and denial of service due to masked path abuse
• CVE-2025-52881: fix container escape and denial of service due to procfs write redirects
• remove obsolete CVE-2023-27561_CVE-2023-28642.patch (fixes included in 1.2.8)
• add no_openssl build tag to prevent use of vendored crypto libraries
• add runc_dmz_selinux_nocompat build tag for SELinux DMZ feature support
• add container-selinux >= 2.224.0 dependency for DMZ SELinux feature

AppArmor bypass with symlinked /proc in github.com/opencontainers/runc

/sys/fs/cgroup is writable when cgroupns isn't unshared (CVE-2023-25809) Regression that reintroduced CVE-2019-19921 - Incorrect Access Control leading to Escalation of Privileges (CVE-2023-27561) AppArmor/SELinux bypass with symlinked /proc (CVE-2023-28642)

These are all security issues fixed in the runc-1.1.5-1.1 package on the GA media of openSUSE Tumbleweed.

These are all security issues fixed in the govulncheck-vulndb-0.0.20250807T150727-1.1 package on the GA media of openSUSE Tumbleweed.

This update for runc fixes the following issues:

Update to runc v1.1.5:

Security fixes:

• CVE-2023-25809: Fixed rootless /sys/fs/cgroup is writable when cgroupns isn't unshared (bnc#1209884).
• CVE-2023-27561: Fixed regression that reintroduced CVE-2019-19921 vulnerability (bnc#1208962).
• CVE-2023-28642: Fixed AppArmor/SELinux bypass with symlinked /proc (bnc#1209888).

Other fixes:

• Fix the inability to use /dev/null when inside a container.
• Fix changing the ownership of host's /dev/null caused by fd redirection (bsc#1168481).
• Fix rare runc exec/enter unshare error on older kernels.
• nsexec: Check for errors in write_log().
• Drop version-specific Go requirement.

This update for runc fixes the following issues:

Update to runc v1.1.5:

Security fixes:

• CVE-2023-25809: Fixed rootless /sys/fs/cgroup is writable when cgroupns isn't unshared (bnc#1209884).
• CVE-2023-27561: Fixed regression that reintroduced CVE-2019-19921 vulnerability (bnc#1208962).
• CVE-2023-28642: Fixed AppArmor/SELinux bypass with symlinked /proc (bnc#1209888).

Other fixes:

• Fix the inability to use /dev/null when inside a container.
• Fix changing the ownership of host's /dev/null caused by fd redirection (bsc#1168481).
• Fix rare runc exec/enter unshare error on older kernels.
• nsexec: Check for errors in write_log().
• Drop version-specific Go requirement.

It was discovered that runC incorrectly made /sys/fs/cgroup writable when in rootless mode. An attacker could possibly use this issue to escalate privileges. (CVE-2023-25809)

It was discovered that runC incorrectly performed access control when mounting /proc to non-directories. An attacker could possibly use this issue to escalate privileges. (CVE-2023-27561)

It was discovered that runC incorrectly handled /proc and /sys mounts inside a container. An attacker could possibly use this issue to bypass AppArmor, and potentially SELinux. (CVE-2023-28642)

USN-6088-1 fixed vulnerabilities in runC. This update provides the corresponding updates for Ubuntu 16.04 LTS.

It was discovered that runC incorrectly performed access control when mounting /proc to non-directories. An attacker could possibly use this issue to escalate privileges. (CVE-2019-19921)

Felix Wilhelm discovered that runC incorrecly handled netlink messages. An attacker could possibly use this issue to escalate privileges. (CVE-2021-43784)

Andrew G. Morgan discovered that runC incorrectly set inherited process capabilities inside the container. An attacker could possibly use this issue to escalate privileges. (CVE-2022-29162)

Original advisory details:

It was discovered that runC incorrectly made /sys/fs/cgroup writable when in rootless mode. An attacker could possibly use this issue to escalate privileges. (CVE-2023-25809)

It was discovered that runC incorrectly performed access control when mounting /proc to non-directories. An attacker could possibly use this issue to escalate privileges. (CVE-2023-27561)

It was discovered that runC incorrectly handled /proc and /sys mounts inside a container. An attacker could possibly use this issue to bypass AppArmor, and potentially SELinux. (CVE-2023-28642)