6.8

CVE-2026-26054: sumatrapdfreader sumatrapdf Out-of-bounds Read

CVSS: 6.8v4.0MediumDeferred
Published 24-09-2026Last modified 28-09-2026
Open JSON

Vulnerability summary

CVE-2026-26054 is a medium (CVSS 6.8) Out-of-bounds Read vulnerability in sumatrapdfreader sumatrapdf. EPSS estimates a 0.14% chance of exploitation in the next 30 days, higher than 2.6% of scored vulnerabilities.

Overall risk
27/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.8/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.14%
0%100%
Low · Change unavailable
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 24-09-2026
    PublishedVulnerability first disclosed.
  2. 28-09-2026
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.14%

Chance of exploitation in the next 30 days

Percentile

3%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

25-09-202621-10-2026
EPSS score
0.14%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Sumatrapdfreader1 product

1 vendor · 1 product

References

4 links