The nameserver caching daemon (nscd) in the GNU C Library (aka glibc or libc6) 2.29…
Priority LOW 13CWE-415Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- High
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · Low
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00385 32nd percentileScored 2026-11-07
Fix Fixed Red Hat: 1 advisory
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
CPE configurations NVD · 4
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:gnu:glibc:*:*:*:*:*:*:*:* | 2.29 – 2.33 | Vulnerable | GNU |
| cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* | 33 | Vulnerable | Fedoraproject |
| cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* | 34 | Vulnerable | Fedoraproject |
| cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* | 10.0 | Vulnerable | Debian |
- cpe:2.3:a:gnu:glibc:*:*:*:*:*:*:*:* Versions 2.29 – 2.33 Vulnerable ·GNU
- cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* Versions 33 Vulnerable ·Fedoraproject
- cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* Versions 34 Vulnerable ·Fedoraproject
- cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* Versions 10.0 Vulnerable ·Debian
Remediation
Red Hat 1 advisory
- RHSA-2021:4358 Released 2021-11-09 · Red Hat rating Moderateglibc security, bug fix, and enhancement update
- Red Hat CodeReady Linux Builder (v. 8) glibc-benchtests-2.28-164.el8, glibc-nss-devel-2.28-164.el8, glibc-static-2.28-164.el8 +1
- Red Hat Enterprise Linux AppStream (v. 8) compat-libpthread-nonshared-2.28-164.el8, glibc-utils-2.28-164.el8
- Red Hat Enterprise Linux BaseOS (v. 8) glibc-2.28-164.el8, glibc-all-langpacks-2.28-164.el8, glibc-common-2.28-164.el8 +47
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat CodeReady Linux Builder (v. 8) | Fixed | RHSA-2021:4358 |
| Red Hat Enterprise Linux AppStream (v. 8) | Fixed | RHSA-2021:4358 |
| Red Hat Enterprise Linux BaseOS (v. 8) | Fixed | RHSA-2021:4358 |
Not affected: 3 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2021-27645
- 2026-10-03 Alias added: GHSA-2hpw-5cjm-953f
References
Sources
- CVE-2021-27645 · CVE Program
- CVE-2021-27645 · NVD
- FIRST EPSS
- GHSA-2hpw-5cjm-953f · GitHub Advisory Database · CC BY 4.0
- CVE-2021-27645 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences