Vulnerability

CVE-2026-33999

High· 7.8ZDICVSS7.8EPSS0%

.rules3/5

ZDI-26-333: X.Org Server XkbSetCompatMap Integer Underflow Privilege Escalation Vulnerability

This vulnerability allows local attackers to escalate privileges on affected installations of X.Org Server. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. The ZDI has assigned a CVSS rating of 7.8. The following CVEs are assigned: CVE-2026-33999.

Threat signal

78/100

High

Severity

high

CVSS

7.8

EPSS

Active

CVSS

v3.1via NVDOpen in FIRST calculator →

7.8/ 10HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack VectorLocalRequires local access — shell, console, or local app.
Attack ComplexityLowNo special conditions — exploit works reliably.
Privileges RequiredLowStandard user privileges sufficient.
User InteractionNoneFully automated — no victim action needed.
ScopeUnchangedImpact contained to the vulnerable component.
Confidentiality ImpactHighTotal disclosure of sensitive data.
Integrity ImpactHighTotal compromise of integrity — full data modification possible.
Availability ImpactHighTotal loss of availability — full DoS possible.

EPSS

Exploit prediction · 30-day horizonFIRST.org →

0.01%

probability of exploitation in next 30 days

higher than 0% of all CVEs

3-day trend↑ 0pp

Low exploitation likelihood — defer if no other signals fire.

Vendor VEX

No VEX statements published for CVE-2026-33999. Vendors publish VEX (Vulnerability Exploitability eXchange) to assert per-product whether a CVE is actually exploitable in their distribution.

SSVCTrack

Total impact on non-trivial mission systems

exploitation: none
automatable: no
impact: total
mission: support

Lifecycle

2026-04-30Vendor advisory · amazon-linuxALAS2-2026-3268 — ALAS2-2026-3268 (important): xorg-x11-server
2026-04-30Vendor advisory · amazon-linuxALAS2-2026-3273 — ALAS2-2026-3273 (important): tigervnc
2026-06-09Published
2026-06-09Last modified2 sources

Entity graph

3 nodes · 2 edges · click to pivot

CVEActorVendor advisoryIOCNews

Vendor advisories

References

No source-event history recorded yet. New revisions will appear here as ingestors re-fetch this CVE.