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CVE-2026-86140: xmlsoft libxml2 Stack-based Buffer Overflow

CVSS: 8.0v3.1HighAnalyzed
AliasesUBUNTU-CVE-2026-86140DEBIAN-CVE-2026-86140
Published 05-09-2026Last modified 08-09-2026
Open JSON

Vulnerability summary

CVE-2026-86140 is a high (CVSS 8.0) Stack-based Buffer Overflow vulnerability in xmlsoft libxml2. EPSS estimates a 0.16% chance of exploitation in the next 30 days, higher than 4.4% of scored vulnerabilities.

Overall risk
32/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.0/10
010
High · v3.1 (CVE.org)
EPSS score
0.16%
0%100%
Low · +0.01 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 6 · Related 1
MGASA-2026-0459RHSA-2026:64463RHSA-2026:71585RHSA-2026:71586RHSA-2026:71641USN-8787-1

Timeline

  1. 05-09-2026
    PublishedVulnerability first disclosed.
  2. 08-09-2026
    Last modifiedVulnerability information updated.

Description

In libxml2 before 2.15.4, xmlSnprintfElements in valid.c has a strcat stack-based buffer overflow.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.16%

Chance of exploitation in the next 30 days

Percentile

4%

Versus all other CVEs

30-day change

+0.01 pp

From 0.15% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.16%

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

Debian1 product
  • libxml2All versions (No fix recorded) | < 2.15.4+dfsg-1
Ubuntu1 product
  • libxml2< 2.9.1+dfsg1-3ubuntu4.13+esm12 | < 2.9.3+dfsg1-1ubuntu0.7+esm13 | < 2.9.4+dfsg1-6.1ubuntu1.9+esm8 | < 2.9.10+dfsg-5ubuntu0.20.04.10+esm5 | < 2.9.13+dfsg-1ubuntu0.13 | < 2.9.14+dfsg-1.3ubuntu3.9 | < 2.15.2+dfsg-0.1ubuntu0.2
Xmlsoft1 product

3 vendors · 3 products

References

7 links