CVE-2026-25920: sumatrapdfreader sumatrapdf Out-of-bounds Read
Vulnerability summary
CVE-2026-25920 is a medium (CVSS 5.5) Out-of-bounds Read vulnerability in sumatrapdfreader sumatrapdf. EPSS estimates a 0.26% chance of exploitation in the next 30 days, higher than 17.1% of scored vulnerabilities. 1 public exploit is recorded.
Timeline
- 09-02-2026PublishedVulnerability first disclosed.
- 11-02-2026Last modifiedVulnerability information updated.
Description
SumatraPDF is a multi-format reader for Windows. In 3.5.2 and earlier, a heap out-of-bounds read vulnerability exists in SumatraPDF's MOBI HuffDic decompressor. The bounds check in AddCdicData() only validates half the range that DecodeOne() actually accesses. Opening a crafted .mobi file can read nearly (1 << codeLength) bytes beyond the CDIC dictionary buffer, leading to a crash.
CVSS metrics
2 scores · 2 sources · 1 version- NVDNIST5.5MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.26%
Chance of exploitation in the next 30 days
Percentile
17%
Versus all other CVEs
30-day change
+0.04 pp
From 0.23% on 21-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundSumatrapdf
Maturity: poc
Weaknesses
CWE · root causeAffected systems
Sumatrapdfreader1 product
- sumatrapdf≤ 3.5.2
1 vendor · 1 product
References
3 links- github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-5mwx-65x7-cffpX Refsource CONFIRMExploitVendor Advisory
- github.com/sumatrapdfreader/sumatrapdf/commit/12b6887e9dfff874fe8749bab1bdc53d4ff075b3X Refsource MISCProduct