Out-of-Bounds Write in Gnu Glibc (CVE-2026-5435)
Summary
Out-of-bounds write in Gnu Glibc (CVE-2026-5435). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
The deprecated functions ns_printrrf, ns_printrr and fp_nquery in the GNU C Library version 2.2 and newer fail to enforce the caller-supplied buffer length, and can result in an out-of-bounds write when printing TSIG records.
Source: NIST National Vulnerability Database 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-2026-5435 has been found in Gnu Glibc.
Risk of unauthorized operations or information disclosure. CVSS score: 7.3/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Gnu Glibc CVE-2026-5435" on the vendor's site.
CVE-2026-5435 (Gnu Glibc) — CWE-787 / CVSS v3 7.3
Attack vector: remote (network-reachable) / unauthenticated / 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.
Out-of-bounds write (CWE-787) exists in Gnu Glibc.
Check the vendor advisory for the affected versions of Gnu Glibc.
Severity: High (CVSS 7.3/10). 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. Run grep -r 'Glibc' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'Glibc' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
Glibcを grep し、稼働しているサービス・バージョンを把握する。 -
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。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-5435 glibc
- Ubuntu UBUNTU-CVE-2026-5435 eglibc
References
- web inbox.sourceware.org
- web sourceware.org
- web cert-portal.siemens.com
- web nvd.nist.gov
- web github.com