DEBIAN-CVE-2026-44950

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    DEBIAN-CVE-2026-44950

    Published: 10 Sept 2026Last Modified: 11 Sept 2026
    Upstream:
    CVE-2026-44950

    Summary:

    Details: fs_read_glyphs() in the libXfont2 font-server client (src/fc/fserve.c) copies each glyph's bitmap into a single buffer. Existing checks validates only that the source slice (position, length) lies within the source bitmap buffer. It does not check whether the running destination cursor has exceeded the allocation. A malicious font server can send overlapping source offsets -- for example 1000 glyphs each referencing {position:0, length:64} with nbytes=64. Each individual source range passes the existing validation, but the cumulative writes total 64000 bytes into a 64-byte destination buffer. This is a heap buffer overflow with attacker-controlled content.

    References: https://security-tracker.debian.org/tracker/CVE-2026-44950

    Affected packages

    Package

    Name: libxfont

    Purl: pkg:deb/debian/libxfont?arch=source&distro=bookworm

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -None

    Affected versions

    1:2.0.6-1
    1:2.0.6-1+deb12u1
    1:2.0.6-1+hurd.1
    1:2.0.6-2
    1:2.0.8-1
    1:2.0.9-1

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    DEBIAN-CVE-2026-44950 | CVE-DB