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CVE-2026-33999VulnerabilityPublished Updated

Red Hat Security Advisory: xorg-x11-server security update

Affects Red Hat xorg-x11-serverSource GCVE Database

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Mentioned vulnerabilities

Authoritative record:CVE-2026-33999· High 7.8

Not known to be exploited · CVSS 7.8 High.

Data as of 6 Nov 2026, 02:47 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.

Sources agree

CVSS scores by source
CNA (redhat)CVSS 3.17.8
ADP (redhat-SADP)CVSS 3.17.8
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 23 Apr 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.

What to do

Affected software

ProductAffectedFixed in
Red Hat Enterprise Linux 10xorg-x11-server-XwaylandAffected–Fixed in–
Red Hat Enterprise Linux 10xorg-x11-server-XwaylandAffected–Fixed in–
Red Hat Enterprise Linux 10.0 Extended Update Supportxorg-x11-server-XwaylandAffected–Fixed in–
Red Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSIONtigervncAffected–Fixed in–
Red Hat Enterprise Linux 7 Extended Lifecycle Supportxorg-x11-serverAffected–Fixed in–
Red Hat Enterprise Linux 7 Extended Lifecycle SupporttigervncAffected–Fixed in–

AI-suggested

Red Hat has released security updates for xorg-x11-server in Red Hat Enterprise Linux 9 and related variants that address these vulnerabilities. Users should apply the updates as described in the Red Hat advisory (RHSA-2026:19343) to remediate these issues. No additional mitigation steps are indicated beyond applying the official patches.

Description

Multiple security vulnerabilities have been identified in the X.Org X server component xwayland, affecting Red Hat Enterprise Linux 9. These include a denial of service via integer underflow in XKB compatibility map handling (CVE-2026-33999), a use-after-free vulnerability that can lead to server crash and potential memory corruption (CVE-2026-34001), and information exposure and denial of service via out-of-bounds memory access (CVE-2026-34003). Red Hat has released security updates addressing these issues.

References

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