CVE-2026-33999
HIGHCVSS 7.8/10EPSS 0.38%
Last modified
CVE-2026-33999 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. 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. EPSS estimates a 0.38% chance of exploitation in the next 30 days.
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.
Metrics
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness Enumeration
Affected Software
Source: CNA advisory (CVE.org). NVD analysis pending.
| Vendor | Product | Versions |
|---|---|---|
| Red Hat | Red Hat Enterprise Linux 10 | All versions |
| Red Hat | Red Hat Enterprise Linux 10.0 Extended Update Support | All versions |
| Red Hat | Red Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSION | All versions |
| Red Hat | Red Hat Enterprise Linux 7 Extended Lifecycle Support | All versions |
| Red Hat | Red Hat Enterprise Linux 8 | All versions |
| Red Hat | Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | All versions |
| Red Hat | Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | All versions |
| Red Hat | Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | All versions |
| Red Hat | Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On | All versions |
| Red Hat | Red Hat Enterprise Linux 8.6 Telecommunications Update Service | All versions |
| Red Hat | Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions | All versions |
| Red Hat | Red Hat Enterprise Linux 8.8 Telecommunications Update Service | All versions |
| Red Hat | Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | All versions |
| Red Hat | Red Hat Enterprise Linux 9 | All versions |
| Red Hat | Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions | All versions |
| Red Hat | Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | All versions |
| Red Hat | Red Hat Enterprise Linux 9.4 Extended Update Support | All versions |
| Red Hat | Red Hat Enterprise Linux 9.6 Extended Update Support | All versions |
| Red Hat | Red Hat Enterprise Linux 6 | All versions |
References
Timeline
- Published
- Last Modified
- Status
- Awaiting Analysis
Frequently Asked Questions
What is CVE-2026-33999?
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.
How severe is CVE-2026-33999?
CVE-2026-33999 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.38% probability of exploitation in the next 30 days.
How do I fix CVE-2026-33999?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
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Are you affected by CVE-2026-33999?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST