CVE catalog

CVE-2021-27645

glibc: CVE-2021-27645

Severity: Low · CVSS 2.5CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
Published: Feb 24, 2021, 3:15:00 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.39% · Oct 22, 2026

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.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	glibc	sid	`2.43-7`	fixed
Debian	glibc	forky	`2.43-7`	fixed
Debian	glibc	trixie	`2.41-12+deb13u4`	fixed
Debian	glibc	bookworm	`2.36-9+deb12u14`	fixed
Debian	glibc	bookworm-security	`2.36-9+deb12u7`	fixed
Cpe	glibc	Not reported	Not reported	unknown
Cpe	fedora	Not reported	Not reported	unknown
Cpe	debian_linux	Not reported	Not reported	unknown
Ubuntu	glibc	20.04	`2.30-0ubuntu2`	vulnerable
Ubuntu	glibc	20.04	`2.30-0ubuntu3`	vulnerable
Ubuntu	glibc	20.04	`2.31-0ubuntu5`	vulnerable
Ubuntu	glibc	20.04	`2.31-0ubuntu6`	vulnerable
Ubuntu	glibc	20.04	`2.31-0ubuntu7`	vulnerable
Ubuntu	glibc	20.04	`2.31-0ubuntu9`	vulnerable
Ubuntu	glibc	20.04	`2.31-0ubuntu9.1`	vulnerable
Ubuntu	glibc	20.04	`2.31-0ubuntu9.2`	vulnerable
Ubuntu	glibc	20.04	`2.31-0ubuntu9.3`	vulnerable
Ubuntu	glibc	20.04	`2.31-0ubuntu9.7`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	glibc	source	sid	`2.31-10`	not yet assigned	Not reported	[983479]
Debian	glibc	source	forky	`2.31-10`	not yet assigned	Not reported	[983479]
Debian	glibc	source	trixie	`2.31-10`	not yet assigned	Not reported	[983479]
Debian	glibc	source	bookworm	`2.31-10`	not yet assigned	Not reported	[983479]
Ubuntu	glibc	deb	20.04	`2.31-0ubuntu9.7`	Not reported	UBUNTU-CVE-2021-27645	Not reported

[Debian bug #983479]

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[glibc-doc]Fixed
Source package: [glibc]
Details (4)
- 2.36-9+deb12u14 · all · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u14 · all · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · all · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · all · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
[glibc-source]Fixed
Source package: [glibc]
Details (4)
- 2.36-9+deb12u14 · all · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u14 · all · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · all · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · all · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
[libc6]Fixed
Source package: [glibc]
Details (4)
- 2.36-9+deb12u14 · amd64 · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u14 · arm64 · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · amd64 · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · arm64 · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
[libc6-dbg]Fixed
Source package: [glibc]
Details (4)
- 2.36-9+deb12u14 · amd64 · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u14 · arm64 · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · amd64 · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · arm64 · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
[libc6-dev]Fixed
Source package: [glibc]
Details (4)
- 2.36-9+deb12u14 · amd64 · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u14 · arm64 · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · amd64 · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · arm64 · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
[libc6-dev-i386]Fixed
Source package: [glibc]
Details (2)
- 2.36-9+deb12u14 · amd64 · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · amd64 · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
[libc6-dev-x32]Fixed
Source package: [glibc]
Details (2)
- 2.36-9+deb12u14 · amd64 · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · amd64 · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
[libc6-i386]Fixed
Source package: [glibc]
Details (2)
- 2.36-9+deb12u14 · amd64 · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · amd64 · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
[libc6-x32]Fixed
Source package: [glibc]
Details (2)
- 2.36-9+deb12u14 · amd64 · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · amd64 · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
[libc-bin]Fixed
Source package: [glibc]
Details (4)
- 2.36-9+deb12u14 · amd64 · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u14 · arm64 · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · amd64 · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · arm64 · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
[libc-dev-bin]Fixed
Source package: [glibc]
Details (4)
- 2.36-9+deb12u14 · amd64 · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u14 · arm64 · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · amd64 · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · arm64 · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
[libc-devtools]Fixed
Source package: [glibc]
Details (4)
- 2.36-9+deb12u14 · amd64 · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u14 · arm64 · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · amd64 · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · arm64 · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
[libc-l10n]Fixed
Source package: [glibc]
Details (4)
- 2.36-9+deb12u14 · all · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u14 · all · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · all · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · all · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
[locales]Fixed
Source package: [glibc]
Details (4)
- 2.36-9+deb12u14 · all · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u14 · all · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · all · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · all · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
[locales-all]Fixed
Source package: [glibc]
Details (4)
- 2.36-9+deb12u14 · amd64 · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u14 · arm64 · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · amd64 · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · arm64 · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
[nscd]Fixed
Source package: [glibc]
Details (4)
- 2.36-9+deb12u14 · amd64 · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u14 · arm64 · bookworm
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · amd64 · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm
- 2.36-9+deb12u7 · arm64 · bookworm-security
  Fixed · Fixed: 2.31-10
  dsa · glibc · debian · bookworm

Observed: Oct 23, 2026, 5:55:27 PM UTC

References

[CERT-Bund public advisories] · [CISA cybersecurity advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]