CVE-2026-86143
Low
No strong exploitation signal.
CVSS base
6.9
MEDIUM
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L
EPSS — probability of exploitation (30 days)
0.1%
2.7th percentile
CISA KEV
Not listed
Weakness / dates
CWE-192
Published 2026-09-05 · modified 2026-09-15
CVSS breakdown
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L
| Attack Vector | L | Local |
| Attack Complexity | H | High |
| Privileges Required | N | None |
| User Interaction | N | None |
| Scope | U | Unchanged |
| Confidentiality | H | High |
| Integrity | H | High |
| Availability | L | Low |
Timeline
- 2026-09-05 — Published (NVD)
- 2026-09-15 — Last modified (NVD)
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.