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High 7.8Published Apr 23, 2026

CVE-2026-33999Xorg: xwayland: x.org x server: denial of service via integer underflow in xkb compatibility map handling

Updated under an hour ago ()

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It affects Red Hat Enterprise Linux 10 and 7 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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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
7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE)
CWE-191
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
redhat
NVD analysis
Awaiting Analysis
Record last updated
Jul 14, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
from 0:24.1.5-6.el10_1 not affected
CNA record
from 0:24.1.5-6.el10_0 not affected
CNA record
from 0:1.1.0-25.el6_10.16 not affected
CNA record
from 0:1.20.10-4.el8_4 not affected
CNA record
from 0:1.20.10-4.el8_4 not affected
CNA record
from 0:21.1.3-2.el8_6.6 not affected
CNA record
from 0:21.1.3-2.el8_6.6 not affected
CNA record
from 0:1.20.11-28.el9_4 not affected
CNA record
from 0:24.1.5-6.el10_1 not affected; from 0:24.1.9-4.el10_2 not affected
CISA ADP
from 0:24.1.5-6.el10_0 not affected
CISA ADP

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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