CVE-2026-86139: xmlsoft libxml2 Integer Overflow or Wraparound
CVSS: 7.8v3.1HighAnalyzed
AliasesUBUNTU-CVE-2026-86139DEBIAN-CVE-2026-86139
Published 05-09-2026Last modified 08-09-2026
Vulnerability summary
CVE-2026-86139 is a high (CVSS 7.8) Integer Overflow or Wraparound vulnerability in xmlsoft libxml2. EPSS estimates a 0.17% chance of exploitation in the next 30 days, higher than 5.5% of scored vulnerabilities.
CVSS score
7.8/10
010
High · v3.1 (NVD)EPSS score
0.17%
0%100%
Low · +0.05 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 3 · Related 1Timeline
- 05-09-2026PublishedVulnerability first disclosed.
- 08-09-2026Last modifiedVulnerability information updated.
Description
In libxml2 before 2.15.4, xmlURIEscapeStr in uri.c has an integer overflow.
CVSS metrics
4 scores · 4 sources · 1 versionHigh 7.8Preferred score · NVD (NIST)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HSources4 sources · 6.9–7.8
- CVE.orgCNA6.9MediumCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:LDiffers
- OSV · UbuntuEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.17%
Chance of exploitation in the next 30 days
Percentile
6%
Versus all other CVEs
30-day change
+0.05 pp
From 0.11% on 20-09-2026
20-09-202620-10-2026
EPSS score0.17%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Debian1 product
- libxml2All versions (No fix recorded) | < 2.15.4+dfsg-1
Ubuntu1 product
- libxml2< 2.15.2+dfsg-0.1ubuntu0.3
Xmlsoft1 product
- libxml2< 2.15.4
3 vendors · 3 products
References
6 links- github.com/GNOME/libxml2/compare/v2.15.3...v2.15.4Release Notes
