CVE-2026-260546.8MediumCWE-125

CVE-2026-26054: SumatraPDF: Heap out-of-bounds read in MOBI header parser.

sumatrapdfreader · sumatrapdf

Affected: sumatrapdfreader · Exploitation: unlikely (under 1%)

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

0.2%probability of exploitation in the next 30 days

11th percentile

050100

Higher than 11% of scored CVEs

6.8MediumCVSS 4.0

LowMediumHighCrit.

DescriptionCVE.org

SumatraPDF is a multi-format reader for Windows. Prior to 3.6, the MobiDoc::ParseHeader function in src/MobiDoc.cpp validates a record using kMobiHeaderMinLen but DecodeMobiDocHeader constructs a decoder sized for kMobiHeaderLen without receiving the actual remaining buffer length. A malformed MOBI file can use an attacker-controlled header length to bypass optional-field early returns and cause the decoder to read beyond a short heap buffer. Opening the crafted document can crash SumatraPDF. This issue is fixed in version 3.6.

Affected products1

From the CVE record. A product or version that is not listed is unknown, not unaffected.

sumatrapdfreader · sumatrapdf< 3.6

On the Atlas

Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.

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Exploitation: Unlikely (under 1%). EPSS under 1%, or no score yet.
CISA KEV: Not listed
Public check: No public nuclei template
Weakness: Out-of-bounds Read · Memory Corruption
Vendor: sumatrapdfreader
Published: September 2026
Band: Unlikely (under 1%), September 2026

CoverageNo articles yet

No CyberSIXT article names CVE-2026-26054 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.