CVE-2026-33999: Integer Underflow (Wrap or Wraparound) in Red Hat Red Hat Enterprise Linux 10
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.
AI Analysis
Technical Summary
An integer underflow in the X.Org X server's XKB compatibility map handling component allows local or remote attackers with X11 server access to cause a buffer read overrun. This memory safety violation can lead to denial of service or other serious impacts. The vulnerability affects Red Hat Enterprise Linux versions 9.0 through before 9.8 and 10.0 through before 10.2. Red Hat has released security updates for the xorg-x11-server-Xwayland and tigervnc packages to fix this issue, as documented in RHSA-2026:10739 and RHSA-2026:11352 advisories. The CVSS v3.1 base score is 7.8 with vector AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, indicating high impact on confidentiality, integrity, and availability.
Potential Impact
Successful exploitation of this integer underflow can cause buffer read overruns leading to memory safety violations. This may result in denial of service conditions or potentially more severe impacts such as memory corruption. The vulnerability requires local or remote access to the X11 server and privileges at the level of local user or remote X11 client. The CVSS score of 7.8 reflects high impact on confidentiality, integrity, and availability.
Mitigation Recommendations
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.
CVE-2026-33999: Integer Underflow (Wrap or Wraparound) in Red Hat Red Hat Enterprise Linux 10
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.
CVSS v3.1
Score 7.8high
Affected software
pkg:rpm/redhat/xorg-x11-server-XwaylandRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
An integer underflow in the X.Org X server's XKB compatibility map handling component allows local or remote attackers with X11 server access to cause a buffer read overrun. This memory safety violation can lead to denial of service or other serious impacts. The vulnerability affects Red Hat Enterprise Linux versions 9.0 through before 9.8 and 10.0 through before 10.2. Red Hat has released security updates for the xorg-x11-server-Xwayland and tigervnc packages to fix this issue, as documented in RHSA-2026:10739 and RHSA-2026:11352 advisories. The CVSS v3.1 base score is 7.8 with vector AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, indicating high impact on confidentiality, integrity, and availability.
Potential Impact
Successful exploitation of this integer underflow can cause buffer read overruns leading to memory safety violations. This may result in denial of service conditions or potentially more severe impacts such as memory corruption. The vulnerability requires local or remote access to the X11 server and privileges at the level of local user or remote X11 client. The CVSS score of 7.8 reflects high impact on confidentiality, integrity, and availability.
Mitigation Recommendations
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.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- redhat
- Date Reserved
- 2026-03-25T04:53:13.614Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
- Vendor Advisory Urls
- [{"url":"https://access.redhat.com/security/cve/CVE-2026-33999","vendor":"Red Hat"}]
Threat ID: 69ea9e7887115cfb686fc422
Added to database: 04/23/2026, 22:34:32 UTC
Last enriched: 07/15/2026, 09:01:15 UTC
Last updated: 07/31/2026, 19:22:58 UTC
Views: 105
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