CVE-2026-86137: xmlsoft libxml2 Out-of-bounds Read
CVSS: 6.1v3.1MediumAnalyzed
AliasesUBUNTU-CVE-2026-86137DEBIAN-CVE-2026-86137
Published 05-09-2026Last modified 14-09-2026
Vulnerability summary
CVE-2026-86137 is a medium (CVSS 6.1) Out-of-bounds Read vulnerability in xmlsoft libxml2. EPSS estimates a 0.19% chance of exploitation in the next 30 days, higher than 8.6% of scored vulnerabilities. 1 public exploit is recorded.
CVSS score
6.1/10
010
Medium · v3.1 (NVD)EPSS score
0.19%
0%100%
Low · +0.07 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1reference
Advisory lineage
Upstream 0 · Downstream 2Timeline
- 05-09-2026PublishedVulnerability first disclosed.
- 14-09-2026Last modifiedVulnerability information updated.
Description
In libxml2 before 2.15.4, xmlFAParsePosCharGroup has an out-of-bounds read, aka an out-of-bounds read in the NXT macro in xmlregexp.
CVSS metrics
4 scores · 4 sources · 1 versionMedium 6.1Preferred score · NVD (NIST)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:LSources4 sources · 2.9–6.1
- CVE.orgCNA2.9LowCVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:LDiffers
- OSV · UbuntuEcosystem advisory · calculated6.1MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:L
- OSV · DebianEcosystem advisory · calculated6.1MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:L
EPSS trend
Probability
0.19%
Chance of exploitation in the next 30 days
Percentile
9%
Versus all other CVEs
30-day change
+0.07 pp
From 0.13% on 21-09-2026
21-09-202621-10-2026
EPSS score0.19%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundExploit Reference (gitlab.gnome.org)
Maturity: unknown
Weaknesses
CWE · root causeAffected systems
Debian1 product
- libxml2All versions (No fix recorded) | < 2.15.4+dfsg-1
Ubuntu1 product
- libxml2All versions (No fix recorded)
Xmlsoft1 product
- libxml2< 2.15.4
3 vendors · 3 products
References
7 links- github.com/GNOME/libxml2/compare/v2.15.3...v2.15.4Release Notes
