Out-of-Bounds Read in SumatraPDF is a multi-format reader for Windows. In (CVE-2026-107729)
Summary
Vulnerability in SumatraPDF is a multi-format reader for Windows. In (CVE-2026-107729). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
SumatraPDF is a multi-format reader for Windows. In 3.7.0.22298, src/MobiDoc.cpp narrows the untrusted unsigned mobiHdr.hdrLen field to a signed integer for validation; values above INT_MAX become negative and bypass the upper-bound check. When the EXTH flag is set, the original unsigned value is reused as a pointer offset, causing DecodeExthHeader() to read beyond the record buffer. Opening a crafted MOBI file can reliably terminate the application with a native access violation; no code execution, information disclosure, or integrity impact has been demonstrated. No fixed version is available as of this review.
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-2026-107729 has been found in SumatraPDF is a multi-format reader for Windows. In.
Risk of unauthorized operations or information disclosure. CVSS score: 5.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "SumatraPDF is a multi-format reader for Windows. In CVE-2026-107729" on the vendor's site.
CVE-2026-107729 (SumatraPDF is a multi-format reader for Windows. In) — CWE-125 / CVSS v3 5.5
Attack vector: local / unauthenticated
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 read (CWE-125) exists in SumatraPDF is a multi-format reader for Windows. In.
Check the vendor advisory for the affected versions of SumatraPDF is a multi-format reader for Windows. In.
Severity: Medium (CVSS 5.5/10). 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 SumatraPDF is a multi-format reader for Windows. In 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。