CVE-2026-44950 libXfont2 - Buffer Overflow

libXfont2 contains a heap buffer overflow caused by improper validation of cumulative glyph bitmap copy sizes in fs_read_glyphs(), letting a malicious font server overflow the destination buffer, exploit requires a malicious font server.

CVSS base score 9.0 /10
Critical
CISA KEV
Not listed
Public exploit
None known
EPSS
0.26% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Buffer Overflow
Impact
Remote Code Execution, Denial Of Service
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Published
10 September 2026
Updated
15 October 2026
Weakness
CWE-122

Vendor fix

Update to the latest version of libXfont2 with proper bounds checking.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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