TI-2026-69809 Aliases CVE-2026-107729

Out-of-bounds read in SumatraPDF MOBI parsing crashes the app

LOW 24CWE-125Published 2026-10-08 · Updated 2026-10-09

Key facts

Attack vector: Local
Privileges required: None
User interaction: Required
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: No fix listed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-125 and the CVSS impact.

Summary

SumatraPDF 3.7.0.22298 and earlier, a multi-format reader for Windows, is affected. A narrowing conversion of the untrusted MOBI header length to a signed integer lets oversized values bypass an upper-bound check, so DecodeExthHeader() reads beyond the record buffer (CWE-125). If a user opens a crafted MOBI file, the application can crash with an access violation, and no code execution has been demonstrated.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00146 3rd percentileScored 2026-11-07

Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
sumatrapdfreader	sumatrapdf	up to 3.7.0.22298	—	No fix listed	CNA

sumatrapdf Vendorsumatrapdfreader Affected up to 3.7.0.22298 Fixed in — No fix listed CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPE	Versions	Role	Vendor
cpe:2.3:a:sumatrapdfreader:sumatrapdf::::::::	—	—	sumatrapdfreader

cpe:2.3:a:sumatrapdfreader:sumatrapdf:*:*:*:*:*:*:*:* Versions — — ·sumatrapdfreader

Remediation

The sources list no fixed version for SumatraPDF.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Timeline

2026-10-09 Threatist record created from CVE-2026-107729
2026-10-10 CISA SSVC decision points changed
2026-10-10 Priority changed: MEDIUM → LOW

References

Other 2

TI-2026-18936 SumatraPDF has an Untrusted Search Path in sumatrapdf/src/AppTools.cpp CVSS 3.1HIGH 8.6
TI-2025-35489 A null pointer dereference vulnerability was discovered in SumatraPDF 3.5.2 during the… CVSS 3.1HIGH 7.3
TI-2012-04514 SumatraPDF 2.1.1/MuPDF 1.0 allows remote attackers to cause an Integer Overflow in the… CVSS 3.1HIGH 7.8
TI-2026-69819 Argument injection in SumatraPDF selection translation on Windows CVSS 4.0HIGH 7.1
TI-2026-69814 SumatraPDF: SyncTeX Argument Injection in Inverse Search Enables Arbitrary Command Execution via External Editors CVSS 4.0HIGH 7.1
TI-2026-69813 Null pointer dereference in SumatraPDF CmdExec crashes the reader CVSS 4.0MEDIUM 6.8

See all 26 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences