CVE-2026-86138

HIGHNVD 7.87.8—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.8 under NVD CVSS v3. EPSS exploit probability: 0.1%, top 97% of all CVEs by exploit prediction. GitHub Security Advisory enrichment pending alignment with NVD CVSS.

Triggered by: NVD CVSS baseline
Sources: epss, ghsa, nvd
Trending — 5 sources updated this week
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.8Exploit: None knownExposed: 0

A fix is available — apply it.

In libxml2 before 2.15.4, xmlDictAddQString in dict.c has an integer overflow and resultant heap-based buffer overflow.

CVSS v3
7.8
EG Score
7.8(medium)
EG Risk
35(Track)
EG Risk 35/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity78% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
3%
KEV
Not listed

Published

September 5, 2026

Last Modified

September 15, 2026

Advisory Details (2)

Auto-updated Sep 5, 2026
Upstream fix merged — awaiting tagged release. Sources: github_commit.
github_commit

commit a4cba4b5b5a8 (GNOME/libxml2)

Fix landed in GNOME/libxml2 commit a4cba4b5b5a8 — awaiting tagged release

https://github.com/GNOME/libxml2/commit/a4cba4b5b5a8c42e155ed42d2d2a44955465a2e4
generic

Comparing v2.15.3...v2.15.4 · GNOME/libxml2 · GitHub

https://github.com/GNOME/libxml2/compare/v2.15.3...v2.15.4

Vendor Advisories for CVE-2026-86138(3)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatlibxml2-main-2.15.4-0.1.hum12026-09-06redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFixed inDependents
libxml22.12.3+dfsg-0exp1 ... 2.9.14+dfsg-1.3~deb12u6 (49 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
libxml22.12.7+dfsg+really2.9.14-2.1 ... 2.15.4+dfsg-1 (31 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
libxml22.12.7+dfsg+really2.9.14-2.1 ... 2.15.4+dfsg-1 (28 versions)——

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 36× in last 7d / 63× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-19 05:23 UTCEG score recompute
  2. 2026-09-19 05:23 UTCVendor advisory
  3. 2026-09-19 05:23 UTCGHSA enrichment
  4. 2026-09-18 19:28 UTCEPSS rescore
  5. 2026-09-18 18:23 UTCVendor advisory
  6. 2026-09-18 18:23 UTCGHSA enrichment
  7. 2026-09-18 07:23 UTCVendor advisory
  8. 2026-09-18 07:23 UTCGHSA enrichment
  9. 2026-09-17 20:22 UTCEG score recompute
  10. 2026-09-17 20:22 UTCVendor advisory
  11. 2026-09-17 20:22 UTCGHSA enrichment
  12. 2026-09-17 19:32 UTCEPSS rescore
  13. 2026-09-17 05:22 UTCVendor advisory
  14. 2026-09-17 05:22 UTCGHSA enrichment
  15. 2026-09-16 18:22 UTCEG score recompute
  16. 2026-09-16 18:22 UTCVendor advisory
  17. 2026-09-16 18:22 UTCGHSA enrichment
  18. 2026-09-16 14:09 UTCEPSS rescore
  19. 2026-09-16 06:52 UTCEG score recompute
  20. 2026-09-16 06:52 UTCVendor advisory
  21. 2026-09-16 06:52 UTCGHSA enrichment
  22. 2026-09-16 05:15 UTCEPSS rescore
  23. 2026-09-15 19:52 UTCEG score recompute▲ 0.90
  24. 2026-09-15 19:52 UTCVendor advisory
  25. 2026-09-15 19:52 UTCGHSA enrichment
Show 38 more
  1. 2026-09-15 19:52 UTCNVD updateCVSS v3 → 7.8 · severity → HIGH
  2. 2026-09-15 03:12 UTCEPSS rescore
  3. 2026-09-15 03:12 UTCEPSS rescore
  4. 2026-09-14 23:31 UTCVendor advisory
  5. 2026-09-14 23:31 UTCGHSA enrichment
  6. 2026-09-13 23:02 UTCEG score recompute
  7. 2026-09-13 23:02 UTCVendor advisory
  8. 2026-09-13 23:02 UTCGHSA enrichment
  9. 2026-09-12 23:08 UTCEG score recompute
  10. 2026-09-12 23:08 UTCVendor advisory
  11. 2026-09-12 23:08 UTCGHSA enrichment
  12. 2026-09-11 23:14 UTCEG score recompute
  13. 2026-09-11 23:14 UTCVendor advisory
  14. 2026-09-11 23:14 UTCGHSA enrichment
  15. 2026-09-11 14:53 UTCEPSS rescore
  16. 2026-09-11 14:53 UTCEPSS rescore
  17. 2026-09-10 23:15 UTCEG score recompute
  18. 2026-09-10 23:15 UTCVendor advisory
  19. 2026-09-10 23:15 UTCGHSA enrichment
  20. 2026-09-09 23:21 UTCEG score recompute
  21. 2026-09-09 23:21 UTCVendor advisory
  22. 2026-09-09 23:21 UTCGHSA enrichment
  23. 2026-09-08 22:01 UTCEPSS rescore
  24. 2026-09-08 21:53 UTCVendor advisory
  25. 2026-09-08 21:53 UTCGHSA enrichment
  26. 2026-09-08 19:56 UTCEG score recompute
  27. 2026-09-08 19:56 UTCGHSA enrichment
  28. 2026-09-08 05:12 UTCEG score recompute
  29. 2026-09-08 05:12 UTCGHSA enrichment
  30. 2026-09-07 05:15 UTCEG score recompute
  31. 2026-09-07 05:15 UTCGHSA enrichment
  32. 2026-09-06 13:48 UTCEPSS rescore
  33. 2026-09-06 05:18 UTCEG score recompute
  34. 2026-09-06 05:17 UTCGHSA enrichment
  35. 2026-09-05 15:31 UTCEPSS rescore
  36. 2026-09-05 05:23 UTCEG score recompute
  37. 2026-09-05 04:24 UTCEG score recompute
  38. 2026-09-05 04:23 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-86138?
CVE-2026-86138 is a high vulnerability published on September 5, 2026. In libxml2 before 2.15.4, xmlDictAddQString in dict.c has an integer overflow and resultant heap-based buffer overflow.
When was CVE-2026-86138 disclosed?
CVE-2026-86138 was first published in the National Vulnerability Database on September 5, 2026, with the most recent update on September 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-86138 actively exploited?
CVE-2026-86138 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 97.5% of all scored CVEs.
What is the CVSS score of CVE-2026-86138?
CVE-2026-86138 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2026-86138?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-86138, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-86138

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