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CVE-2026-93990

CVE-2026-93990 · Expat before 2.8.5 Malformed UTF-16 Acceptance via Unchecked Surrogate

This page contains facts from public vulnerability sources. Check the original advisory before updating.

This page shows selected source facts. See the linked advisories for the complete description and affected versions.

Expat before 2.8.5 fails to validate that a high surrogate in UTF-16 input is followed by a low surrogate, allowing malformed UTF-16 sequences to be accepted. Attackers can supply UTF-16 encoded XML containing lone high surrogates that consume the following code unit, causing Expat to pass unpaired surrogates to applications built with XML_UNICODE and to silently replace input characters in other builds.

CVSS 8.7 · High · EPSS 0.4% · Fix available

Published
Updated

Stack: system

Affected products and versions

  • libexpat

    Versions
    • ≥ 0, < 2.8.5: Affected (semver)
    • 2.8.5: Not affected (semver)

    Update to 2.8.5

  • expat Debian:12

    Versions
    • 2.5.0-1
    • 2.5.0-1+deb12u1
    • 2.5.0-1+deb12u2
    • 2.5.0-1+deb12u3
    Affected ranges
    • ECOSYSTEM: < 2.5.0-1+deb12u4

    Update to 2.5.0-1+deb12u4

  • expat Debian:13

    Versions
    • 2.7.1-2
    • 2.7.2-1
    • 2.7.3-1
    • 2.7.3-2
    • 2.7.4-1
    • 2.7.5-1
    • 2.8.0-1
    • 2.8.0-2
    • 2.8.1-1
    • 2.8.2-1
    • 2.8.2-1~deb13u1
    • 2.8.3-1
    • 2.8.3-1~deb13u1
    • 2.8.4-1
    • 2.8.4-2
    • 2.8.5-1
    • 2.8.5-2
    Affected ranges
    • ECOSYSTEM: < 2.9.0-1~deb13u1

    Update to 2.9.0-1~deb13u1

  • expat Debian:14

    Versions
    • 2.7.1-2
    • 2.7.2-1
    • 2.7.3-1
    • 2.7.3-2
    • 2.7.4-1
    • 2.7.5-1
    • 2.8.0-1
    • 2.8.0-2
    • 2.8.1-1
    • 2.8.2-1
    • 2.8.2-1~deb13u1
    • 2.8.3-1
    • 2.8.3-1~deb13u1
    • 2.8.4-1
    Affected ranges
    • ECOSYSTEM: < 2.8.4-2

    Update to 2.8.4-2

  • coin3 Ubuntu:Pro:14.04:LTS

    Versions
    • 3.1.4~abc9f50-3
    • 3.1.4~abc9f50-4
    • 3.1.4~abc9f50-4ubuntu2
    • 3.1.4~abc9f50-4ubuntu2+esm1
    • 3.1.4~abc9f50-4ubuntu2+esm2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • expat Ubuntu:Pro:14.04:LTS

    Versions
    • 2.1.0-4
    • 2.1.0-4ubuntu1
    • 2.1.0-4ubuntu1.1
    • 2.1.0-4ubuntu1.2
    • 2.1.0-4ubuntu1.3
    • 2.1.0-4ubuntu1.4
    • 2.1.0-4ubuntu1.4+esm1
    • 2.1.0-4ubuntu1.4+esm2
    • 2.1.0-4ubuntu1.4+esm4
    • 2.1.0-4ubuntu1.4+esm6
    • 2.1.0-4ubuntu1.4+esm7
    • 2.1.0-4ubuntu1.4+esm8
    • 2.1.0-4ubuntu1.4+esm9
    • 2.1.0-4ubuntu1.4+esm10
    • 2.1.0-4ubuntu1.4+esm11
    • 2.1.0-4ubuntu1.4+esm12
    • 2.1.0-4ubuntu1.4+esm13
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • vnc4 Ubuntu:Pro:14.04:LTS

    Versions
    • 4.1.1+xorg4.3.0-37ubuntu5
    • 4.1.1+xorg4.3.0-37ubuntu5.0.1
    • 4.1.1+xorg4.3.0-37ubuntu5.0.2
    • 4.1.1+xorg4.3.0-37ubuntu5.0.2+esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • vtk Ubuntu:Pro:14.04:LTS

    Versions
    • 5.8.0-14ubuntu1
    • 5.8.0-14ubuntu3
    • 5.8.0-14.1ubuntu2
    • 5.8.0-14.1ubuntu3
    • 5.8.0-14.1ubuntu3+esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • xmlrpc-c Ubuntu:Pro:14.04:LTS

    Versions
    • 1.16.33-3.2ubuntu3
    • 1.33.06-0ubuntu1
    • 1.33.06-0ubuntu1+esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • expat Ubuntu:Pro:16.04:LTS

    Versions
    • 2.1.0-7
    • 2.1.0-7ubuntu0.16.04.1
    • 2.1.0-7ubuntu0.16.04.2
    • 2.1.0-7ubuntu0.16.04.3
    • 2.1.0-7ubuntu0.16.04.4
    • 2.1.0-7ubuntu0.16.04.5
    • 2.1.0-7ubuntu0.16.04.5+esm2
    • 2.1.0-7ubuntu0.16.04.5+esm5
    • 2.1.0-7ubuntu0.16.04.5+esm6
    • 2.1.0-7ubuntu0.16.04.5+esm7
    • 2.1.0-7ubuntu0.16.04.5+esm8
    • 2.1.0-7ubuntu0.16.04.5+esm9
    • 2.1.0-7ubuntu0.16.04.5+esm10
    • 2.1.0-7ubuntu0.16.04.5+esm11
    • 2.1.0-7ubuntu0.16.04.5+esm12
    • 2.1.0-7ubuntu0.16.04.5+esm13
    • 2.1.0-7ubuntu0.16.04.5+esm14
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • ayttm Ubuntu:Pro:16.04:LTS

    Versions
    • 0.6.3-3build1
    • 0.6.3-3ubuntu0.1~esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • cableswig Ubuntu:Pro:16.04:LTS

    Versions
    • 0.1.0+git20150808-1
    • 0.1.0+git20150808-2
    • 0.1.0+git20150808-2ubuntu0.1~esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • cadaver Ubuntu:16.04:LTS

    Versions
    • 0.23.3-2ubuntu2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • coin3 Ubuntu:Pro:16.04:LTS

    Versions
    • 3.1.4~abc9f50+dfsg1-1
    • 3.1.4~abc9f50+dfsg1-1ubuntu0.1~esm1
    • 3.1.4~abc9f50+dfsg1-1ubuntu0.1~esm2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • gdcm Ubuntu:16.04:LTS

    Versions
    • 2.4.4-4
    • 2.4.4-4build1
    • 2.4.4-4ubuntu1
    • 2.6.1-3
    • 2.6.2-1
    • 2.6.2-2
    • 2.6.2-3
    • 2.6.3-1
    • 2.6.3-1ubuntu1
    • 2.6.3-2ubuntu1
    • 2.6.3-3ubuntu1
    • 2.6.3-3ubuntu3
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • insighttoolkit4 Ubuntu:16.04:LTS

    Versions
    • 4.8.1-1ubuntu3
    • 4.8.1-1ubuntu4
    • 4.8.2-3.1ubuntu1
    • 4.9.0-3ubuntu2
    • 4.9.0-4ubuntu1
    • 4.9.0-4ubuntu1.1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • libxmltok Ubuntu:Pro:16.04:LTS

    Versions
    • 1.2-3build3
    • 1.2-3ubuntu0.1~esm1
    • 1.2-3ubuntu0.16.04.1~esm1
    • 1.2-3ubuntu0.16.04.1~esm2
    • 1.2-3ubuntu0.16.04.1~esm3
    • 1.2-3ubuntu0.16.04.1~esm4
    • 1.2-3ubuntu0.16.04.1~esm5
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • matanza Ubuntu:16.04:LTS

    Versions
    • 0.13+ds1-5
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • smart Ubuntu:16.04:LTS

    Versions
    • 1.4-2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • swish-e Ubuntu:Pro:16.04:LTS

    Versions
    • 2.4.7-4
    • 2.4.7-4build1
    • 2.4.7-4ubuntu0.1~esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • tdom Ubuntu:16.04:LTS

    Versions
    • 0.8.3-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • vnc4 Ubuntu:Pro:16.04:LTS

    Versions
    • 4.1.1+xorg4.3.0-37.3ubuntu2
    • 4.1.1+xorg4.3.0-37.3ubuntu2.1+esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • vtk Ubuntu:Pro:16.04:LTS

    Versions
    • 5.10.1+dfsg-2
    • 5.10.1+dfsg-2build3
    • 5.10.1+dfsg-2.1build1
    • 5.10.1+dfsg-2.1ubuntu0.1~esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • wbxml2 Ubuntu:16.04:LTS

    Versions
    • 0.10.7-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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