CVE-2026-107730 sumatrapdfreader CVE debrief

Who should care

Defenders responsible for managing software updates and ensuring the integrity of document readers should assess exposure and verify SumatraPDF versions in use. The vulnerability may lead to application termination upon opening maliciously crafted LIT files, and defenders should prioritize verifying SumatraPDF versions and assessing exposure.

Why it matters

The vulnerability in SumatraPDF 3.7.0.22298 allows for a signed integer overflow when parsing LIT headers, leading to an invalid-pointer read and potential application termination. Defenders should prioritize verifying SumatraPDF versions and assessing exposure.

• Application termination upon opening maliciously crafted LIT files
• Potential for denial-of-service (DoS) attacks
• Need for verification of SumatraPDF versions and exposure

Technical summary

In SumatraPDF 3.7.0.22298, the LitParseHeader() function in src/LitDoc.cpp computes the 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 vulnerability may lead to application termination upon opening maliciously crafted LIT files, and defenders should prioritize verifying SumatraPDF versions and assessing exposure.

Defensive priority

Defenders should prioritize verifying SumatraPDF versions and assessing exposure, as the vulnerability may lead to application termination.

Recommended defensive actions

• Verify SumatraPDF versions in use and assess exposure
• Review system logs for application termination incidents
• Consider compensating controls, such as file format validation
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The supplied evidence does not demonstrate code execution, information disclosure, arbitrary read, or integrity impact. No fixed version is available as of this review. The CVE record was published on 2026-10-08T22:19:46.900Z and has not been modified since then. The NVD entry is currently Medium with a CVSS score of 5.5. The vulnerability in SumatraPDF 3.7.0.22298 allows for a signed integer overflow when parsing LIT headers, leading to an invalid-pointer read and potential application termination.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.