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High 7.8Published Jun 5, 2026

CVE-2026-50256Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: stack buffer overflow in font alias resolution due to libxfont2 name length mismatch

Updated under an hour ago ()

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It affects Red Hat Enterprise Linux 10 and 9 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 stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. A mismatch between the X server and the libXfont2 library's maximum font name length can cause a stack buffer overflow during font alias resolution. The server allocates a 256 byte stack buffer but libXfont2's alias target name length is 1024 bytes. A font alias name between 257 and 1023 bytes causes the X server to copy that name into the undersized stack buffer without further checks. This may be used to crash the server, or for privilege escalation if the X server runs as root.

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-121
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
Modified
Record last updated
Sep 28, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
from 0:24.1.9-4.el10_2.2 not affected
CNA record
from 0:24.1.5-6.el10_0.1 not affected
CNA record
from 0:1.1.0-25.el6_10.18 not affected
CNA record
from 0:1.20.10-5.el8_4 not affected
CNA record
from 0:1.20.10-5.el8_4 not affected
CNA record
from 0:1.20.11-19.el8_8 not affected
CNA record
from 0:1.20.11-19.el8_8 not affected
CNA record
from 0:1.20.11-34.el9_6 not affected
CNA record
from 0:24.1.9-4.el10_2.2 not affected
CISA ADP
from 0:24.1.5-6.el10_0.1 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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CVE-2026-50256: Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: stack buffer overflow in font alias resoluti | InfoSec Signals