CVE-2021-27645

The nameserver caching daemon (nscd) in the GNU C Library (aka glibc or libc6) 2.29 through 2.33, when processing a request for netgroup lookup, may crash due to a double-free, potentially resulting in degraded service or Denial of Service on the local system. This is related to netgroupcache.c.

The glibc packages provide the standard C libraries (libc), POSIX thread libraries (libpthread), standard math libraries (libm), and the name service cache daemon (nscd) used by multiple programs on the system. Without these libraries, the Linux system cannot function correctly.

Security Fix(es):

• glibc: Arbitrary read in wordexp() (CVE-2021-35942)

• glibc: Use-after-free in addgetnetgrentX function in netgroupcache.c (CVE-2021-27645)

• glibc: mq_notify does not handle separately allocated thread attributes (CVE-2021-33574)

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 8.5 Release Notes linked from the References section.

The nameserver caching daemon (nscd) in the GNU C Library (aka glibc or libc6) 2.29 through 2.33, when processing a request for netgroup lookup, may crash due to a double-free, potentially resulting in degraded service or Denial of Service on the local system. This is related to netgroupcache.c.

The glibc packages provide the standard C libraries (libc), POSIX thread libraries (libpthread), standard math libraries (libm), and the name service cache daemon (nscd) used by multiple programs on the system. Without these libraries, the Linux system cannot function correctly.

Security Fix(es):

• glibc: Arbitrary read in wordexp() (CVE-2021-35942)

• glibc: Use-after-free in addgetnetgrentX function in netgroupcache.c (CVE-2021-27645)

• glibc: mq_notify does not handle separately allocated thread attributes (CVE-2021-33574)

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.

• CVE-2021-27645: nscd: Fix double free in netgroupcache (#1927877)
• CVE-2021-33574: Deep copy pthread attribute in mq_notify (#1966472)
• CVE-2021-35942: wordexp: handle overflow in positional parameter number (#1979127)
• librt: fix NULL pointer dereference (#1966472)

Updated glibc packages fix a security vulnerability:

The nameserver caching daemon (nscd), when processing a request for netgroup lookup, may crash due to a double-free, potentially resulting in degraded service or Denial of Service on the local system (CVE-2021-27645).

Updated glibc packages fix a security vulnerabilities:

The iconv function in the GNU C Library (aka glibc or libc6) 2.32 and earlier, when processing invalid multi-byte input sequences in IBM1364, IBM1371, IBM1388, IBM1390, and IBM1399 encodings, fails to advance the input state, which could lead to an infinite loop in applications, resulting in a denial of service (CVE-2020-27618).

The iconv function in the GNU C Library (aka glibc or libc6) 2.32 and earlier, when processing invalid input sequences in the ISO-2022-JP-3 encoding, fails an assertion in the code path and aborts the program, potentially resulting in a denial of service (CVE-2021-3326).

The nameserver caching daemon (nscd), when processing a request for netgroup lookup, may crash due to a double-free, potentially resulting in degraded service or Denial of Service on the local system (CVE-2021-27645).

These are all security issues fixed in the glibc-2.34-1.2 package on the GA media of openSUSE Tumbleweed.

Jan Engelhardt, Tavis Ormandy, and others discovered that the GNU C Library iconv feature incorrectly handled certain input sequences. An attacker could possibly use this issue to cause the GNU C Library to hang or crash, resulting in a denial of service. This issue only affected Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. (CVE-2016-10228, CVE-2019-25013, CVE-2020-27618, CVE-2020-29562, CVE-2021-3326)

Jason Royes and Samuel Dytrych discovered that the GNU C Library incorrectly handled signed comparisons on ARMv7 targets. A remote attacker could use this issue to cause the GNU C Library to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. (CVE-2020-6096)

It was discovered that the GNU C Library nscd daemon incorrectly handled certain netgroup lookups. An attacker could possibly use this issue to cause the GNU C Library to crash, resulting in a denial of service. This issue only affected Ubuntu 20.04 LTS. (CVE-2021-27645)

It was discovered that the GNU C Library wordexp function incorrectly handled certain patterns. An attacker could use this issue to cause the GNU C Library to crash, resulting in a denial of service, or possibly obtain sensitive information. This issue only affected Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. (CVE-2021-35942)

It was discovered that the GNU C Library realpath function incorrectly handled return values. An attacker could possibly use this issue to obtain sensitive information. This issue only affected Ubuntu 21.10. (CVE-2021-3998)

It was discovered that the GNU C library getcwd function incorrectly handled buffers. An attacker could use this issue to cause the GNU C Library to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2021-3999)

It was discovered that the GNU C Library sunrpc module incorrectly handled buffer lengths. An attacker could possibly use this issue to cause the GNU C Library to crash, resulting in a denial of service. (CVE-2022-23218, CVE-2022-23219)