CVE-2026-86143
CVE-2026-86143 is a medium-severity vulnerability in Xmlsoft Libxml2 with a CVSS 3.x base score of 6.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-192.
Key facts
- Severity: Medium (CVSS 3.x base score 6.9)
- EPSS exploit prediction: 0% (8th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-192
- Affected product: Xmlsoft Libxml2
- Published:
- Last modified:
Description
In xmlIO in libxml2 before 2.15.4, an inconsistency in xmlOutputWriteCallback and xmlBufUse causes negative lengths to reach write callbacks, aka a lack of a check for integer overflow before calling writecallback. This has security relevance for many types of uses of that length value within a callback.
Frequently asked questions
- What is CVE-2026-86143?
- In xmlIO in libxml2 before 2.15.4, an inconsistency in xmlOutputWriteCallback and xmlBufUse causes negative lengths to reach write callbacks, aka a lack of a check for integer overflow before calling writecallback. This has security relevance for many types of uses of that length value within a callback.
- How severe is CVE-2026-86143?
- CVE-2026-86143 has a CVSS 3.x base score of 6.9, rated medium severity. It is exploitable over local access with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability low.
- Is CVE-2026-86143 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-86143?
- CVE-2026-86143 affects Xmlsoft Libxml2. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-86143?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- When was CVE-2026-86143 published?
- CVE-2026-86143 was published on 2026-09-05 and last updated on 2026-09-15.
References
- https://github.com/GNOME/libxml2/commit/90f293ba74d28b1d570920382e707586f68ebf35
- https://github.com/GNOME/libxml2/compare/v2.15.3...v2.15.4
- https://gitlab.gnome.org/GNOME/libxml2/-/work_items/1111
Affected products (1)
- cpe:2.3:a:xmlsoft:libxml2:*:*:*:*:*:*:*:*
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