Out-of-Bounds Write in popt (CVE-2026-18739)
Summary
Out-of-bounds write in popt (CVE-2026-18739). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
A flaw was found in popt, a command-line option parsing library. An off-by-one error in the poptStuffArgs function, when repeatedly called by a host application or through deep alias nesting, can lead to corruption of internal program data. This corruption could potentially enable a local attacker to execute arbitrary code if the host application then unsafely processes the altered data.
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-2026-18739 has been found in popt.
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 "popt CVE-2026-18739" on the vendor's site.
CVE-2026-18739 (popt) — CWE-787 / 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.
Out-of-bounds write (CWE-787) exists in popt.
Check the vendor advisory for the affected versions of popt.
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. Run grep -r 'popt' . 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 'popt' . | 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
popt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
- BellSoft Alpaquita BELL-CVE-2026-18739 popt Fixed in: 1.19-r1
- Debian DEBIAN-CVE-2026-18739 popt
- Ubuntu UBUNTU-CVE-2026-18739 popt
References
- web secalert@redhat.com
- web secalert@redhat.com
- web nvd.nist.gov
- web github.com
- web secalert@redhat.com