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CVE-2026-63385

CVE-2026-63385 · Libevent: HTTP header handling bugs create risk of access control bypass.

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

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has two HTTP parsing weaknesses in http.c. evhttp_decode_uri_internal decodes percent-encoded %00 bytes into literal NUL characters, which can cause downstream C string operations to truncate a path and bypass validation performed on a different representation. evhttp_header_is_valid_value also accepts obsolete line folding in header values containing carriage return or line feed characters, allowing a proxy and libevent to interpret headers differently and enabling header injection or access control bypass. The CRLF header acceptance is fixed in versions 2.1.13 and 2.2.2-alpha, but the reviewed patches do not clearly remediate the URI NUL-truncation condition.

CVSS 9.2 · Critical · EPSS 1.3% · Fix available

Published
Updated

Stack: system

Affected products and versions

  • libevent

    Versions
    • >= 2.2.0-alpha, < 2.2.2-alpha: Affected
    • < 2.1.13: Affected

    No fix published

  • libevent Debian:12

    Versions
    • 2.1.12-stable-8
    Affected ranges
    • ECOSYSTEM: < 2.1.12-stable-8+deb12u1

    Update to 2.1.12-stable-8+deb12u1

  • libevent Debian:13

    Versions
    • 2.1.12-stable-10
    Affected ranges
    • ECOSYSTEM: < 2.1.13-stable-1~deb13u1

    Update to 2.1.13-stable-1~deb13u1

  • libevent Debian:14

    Versions
    • 2.1.12-stable-10
    • 2.1.13-stable-1~deb13u1
    Affected ranges
    • ECOSYSTEM: < 2.1.13-stable-1

    Update to 2.1.13-stable-1

  • libevent Ubuntu:Pro:14.04:LTS

    Versions
    • 2.0.21-stable-1
    • 2.0.21-stable-1ubuntu1
    • 2.0.21-stable-1ubuntu1.14.04.1
    • 2.0.21-stable-1ubuntu1.14.04.2
    Affected ranges
    • ECOSYSTEM: < 2.0.21-stable-1ubuntu1.14.04.2+esm1

    Update to 2.0.21-stable-1ubuntu1.14.04.2+esm1

  • libevent Ubuntu:Pro:16.04:LTS

    Versions
    • 2.0.21-stable-2
    • 2.0.21-stable-2ubuntu0.16.04.1
    Affected ranges
    • ECOSYSTEM: < 2.0.21-stable-2ubuntu0.16.04.1+esm1

    Update to 2.0.21-stable-2ubuntu0.16.04.1+esm1

  • libevent Ubuntu:Pro:18.04:LTS

    Versions
    • 2.1.8-stable-4
    • 2.1.8-stable-4build1
    Affected ranges
    • ECOSYSTEM: < 2.1.8-stable-4ubuntu0.1~esm1

    Update to 2.1.8-stable-4ubuntu0.1~esm1

  • libevent Ubuntu:Pro:20.04:LTS

    Versions
    • 2.1.8-stable-4build1
    • 2.1.11-stable-1~exp0
    • 2.1.11-stable-1
    Affected ranges
    • ECOSYSTEM: < 2.1.11-stable-1ubuntu0.1~esm1

    Update to 2.1.11-stable-1ubuntu0.1~esm1

  • libevent Ubuntu:22.04:LTS

    Versions
    • 2.1.12-stable-1
    • 2.1.12-stable-1build1
    • 2.1.12-stable-1build2
    • 2.1.12-stable-1build3
    Affected ranges
    • ECOSYSTEM: < 2.1.12-stable-1ubuntu0.1

    Update to 2.1.12-stable-1ubuntu0.1

  • libevent Ubuntu:24.04:LTS

    Versions
    • 2.1.12-stable-9
    • 2.1.12-stable-9ubuntu2
    Affected ranges
    • ECOSYSTEM: < 2.1.12-stable-9ubuntu2.1

    Update to 2.1.12-stable-9ubuntu2.1

  • libevent Ubuntu:26.04:LTS

    Versions
    • 2.1.12-stable-10build1
    • 2.1.12-stable-10build2
    Affected ranges
    • ECOSYSTEM: < 2.1.12-stable-10ubuntu0.1

    Update to 2.1.12-stable-10ubuntu0.1

Original sources

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