Vulnerability in LIBPNG (CVE-2026-40930)
Summary
Vulnerability in LIBPNG (CVE-2026-40930). Risk of unauthorized operations or information disclosure. Exploitable via png_process_data.
Original description
The description as published by the source.
LIBPNG is a reference library for use in applications that process PNG (Portable Network Graphics) raster image files. In version 1.8.0, three inter-frame chunk discard paths in the push-mode APNG parser clear the chunk-header flag without consuming the chunk body and CRC, allowing attacker-controlled bytes inside an ignored ancillary chunk to be reinterpreted as a fresh chunk header on the next call to png_process_data. Commit faf06924688b62d7c1654b5ceddedbde66ffadb4 fixes the issue.
Source: NIST National Vulnerability Database NVD
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-2026-40930 has been found in LIBPNG.
Attackers can target a specific entry point like png_process_data over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 5.4/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "LIBPNG CVE-2026-40930" on the vendor's site.
CVE-2026-40930 (LIBPNG) — CWE-436 / CVSS v3 5.4
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: png_process_data
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-436) exists in LIBPNG. Attackers reach the vulnerable code path via png_process_data without authentication.
Check the vendor advisory for the affected versions of LIBPNG. Attack surface: png_process_data.
Severity: Medium (CVSS 5.4/10). 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 'LIBPNG' . 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 'LIBPNG' . | 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
LIBPNG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
- Alpine Linux ALPINE-CVE-2026-40930 libpng Fixed in: 1.6.58-r1
- BellSoft Alpaquita BELL-CVE-2026-40930 libpng Fixed in: 1.6.58-r0
- Debian DEBIAN-CVE-2026-40930 libpng1.6
- Ubuntu UBUNTU-CVE-2026-40930 libpng