CVE-2026-33999: Red Hat Enterprise Linux 10 · Integer Underflow
Affects Red Hat Enterprise Linux 10Source CVE Database V5
Not known to be exploited · CVSS 7.8 High · patch available : patch Red Hat Enterprise Linux 10 soon.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 31% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 23 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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 30 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Red Hat Enterprise Linux 10xorg-x11-server-Xwayland | Affected– | Fixed in– |
| Red Hat Enterprise Linux 10xorg-x11-server-Xwayland | Affected– | Fixed in– |
| Red Hat Enterprise Linux 10.0 Extended Update Supportxorg-x11-server-Xwayland | Affected– | Fixed in– |
| Red Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSIONtigervnc | Affected– | Fixed in– |
| Red Hat Enterprise Linux 7 Extended Lifecycle Supportxorg-x11-server | Affected– | Fixed in– |
| Red Hat Enterprise Linux 7 Extended Lifecycle Supporttigervnc | Affected– | Fixed in– |
AI-suggested
Red Hat has released official security updates that address this vulnerability. Users should apply the updates provided in Red Hat Enterprise Linux advisories RHSA-2026:10739 and RHSA-2026:11352. These updates include fixes to the xorg-x11-server-Xwayland and tigervnc packages. Patch status is confirmed by the vendor advisory, and applying these updates will remediate the vulnerability. No additional mitigation steps are indicated by the vendor advisory.
Description
A flaw was found in the X.Org X server. This integer underflow vulnerability, specifically in the XKB compatibility map handling, allows an attacker with local or remote X11 server access to trigger a buffer read overrun. This can lead to memory-safety violations and potentially a denial of service (DoS) or other severe impacts.
References
- access.redhat.com/errata/RHSA-2026:10739 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:11352 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:11369 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:11388 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:11656 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:11692 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:13414 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19125 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19342 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19343 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:19344 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:20547 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:20555 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:20557 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:20558 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:20560 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:20561 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:20562 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:20563 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:20575 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:20576 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:20590 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:21699 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:21712 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:21715 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:21716 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:21718 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:21741 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:21742 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:22424 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:22456 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:23254 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:23255 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:23496 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:24341 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-33999 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2451106 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33999.json (opens in a new tab)