VulnTideExploited vulnerabilities, by vendor. Data as of .
Not in CISA KEVPublished CVSS 7.5 highEPSS 0.2% probability of exploitation in 30 daysFound by AI: Anthropic (Claude)
x.org

CVE-2026-88806: libX11 XkbGetMap Reply Heap-based Buffer Overflow

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of . If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?
0.2%

EPSS score, percentile 10.1 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?
7.5 High

CVSS v3.1 base score, given by the CNA

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

Advisories and patches (1)

Which versions are affected?

Affected

  • before 1.8.14

Versions by product

Source: CISA KEV 2026.10.29, as of ; FIRST EPSS, as of ; CVE List, as of . About the data.

What to do

Advisories and patches

This summary is based on the CVE record as of . Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

As listed in the CVE record.

x.org libX11
StatusVersions
Affectedbefore 1.8.14

Versions not listed are: unaffected.

Source: CVE List, as of . About the data.

About this vulnerability

A malicious X server could exploit a buffer overflow in libX11 before 1.8.14 during handling of XkbGetMap overflowing the key_sym_map.

Summary: CVE record, as of .

  • CISA has not added CVE-2026-88806 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
  • The CVE record was published on 21 Sep 2026.
  • The CVE record carries a CVSS v3.1 base score of 7.5 (High), given by its CNA.
  • FIRST's EPSS model puts the probability of exploitation in the next 30 days at 0.2% (percentile 10.1), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
  • CISA's SSVC assessment in the CVE record: exploitation none, automatable no, technical impact total.
  • The credits in the CVE record name Anthropic (Claude) as finder.

Source: CISA KEV 2026.10.29, as of ; CVE List, as of ; FIRST EPSS, as of . About the data.

Description

libX11 XkbGetMap Reply Heap-based Buffer Overflow

A malicious X server could exploit a buffer overflow in libX11 before 1.8.14 during handling of XkbGetMap overflowing the key_sym_map.

Source: CVE List, as of . About the data.

Weakness

CWE-122, 1 CAPEC
  • CWE-122: Heap-based buffer overflow

Attack patterns (CAPEC)

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record.

Timeline

DateEvent
CVE record published
CVE record last updated