Vulnerability in GNU C Library (CVE-2021-27645)
Summary
Vulnerability in GNU C Library (CVE-2021-27645). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2021-27645 has been found in GNU C Library.
Risk of unauthorized operations or information disclosure. CVSS score: 2.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "GNU C Library CVE-2021-27645" on the vendor's site.
CVE-2021-27645 (GNU C Library) — CWE-415 / CVSS v3 2.5
Attack vector: local / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-415) exists in GNU C Library.
Check the vendor advisory for the affected versions of GNU C Library.
Severity: Low (CVSS 2.5/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで GNU C Library を使っているサービスとバージョンを洗い出す。
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2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- advisory security.gentoo.org
- advisory lists.debian.org
- patch sourceware.org
- web nvd.nist.gov
- web lists.fedoraproject.org
- web lists.fedoraproject.org
- web lists.fedoraproject.org
- web lists.fedoraproject.org
- web cert-portal.siemens.com
- web cert-portal.siemens.com
- web github.com
- web lists.fedoraproject.org
- web lists.fedoraproject.org