How severe is CVE-2026-86140?

CVE-2026-86140 has a CVSS 3.x base score of 8.0, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability low.

Is CVE-2026-86140 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (4th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-86140?

CVE-2026-86140 affects Xmlsoft Libxml2. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-86140?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-86140 published?

CVE-2026-86140 was published on 2026-09-05 and last updated on 2026-09-15.

CVE-2026-86140

CVE-2026-86140 is a high-severity vulnerability in Xmlsoft Libxml2 with a CVSS 3.x base score of 8.0. 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-121.

Key facts

Severity: High (CVSS 3.x base score 8.0)
EPSS exploit prediction: 0% (4th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-121
Affected product: Xmlsoft Libxml2
Published: 2026-09-05
Last modified: 2026-09-15

Description

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

Frequently asked questions

What is CVE-2026-86140?: In libxml2 before 2.15.4, xmlSnprintfElements in valid.c has a strcat stack-based buffer overflow.
How severe is CVE-2026-86140?: CVE-2026-86140 has a CVSS 3.x base score of 8.0, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability low.
Is CVE-2026-86140 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (4th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-86140?: CVE-2026-86140 affects Xmlsoft Libxml2. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-86140?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-86140 published?: CVE-2026-86140 was published on 2026-09-05 and last updated on 2026-09-15.

References

Affected products (1)

cpe:2.3:a:xmlsoft:libxml2:*:*:*:*:*:*:*:*

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