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CVE-2026-11850

CVE-2026-11850 · Krb5: krb5: integer underflow in berval2tl_data() leads to heap out-of-bounds read

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

An integer underflow vulnerability was found in MIT krb5 in the berval2tl_data() function in plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c. The function performs an unsigned subtraction (bv_len - 2) without a prior bounds check. When bv_len is 0 or 1, the subtraction wraps to a large value which is then truncated to uint16_t, yielding 0xFFFE (65534) or 0xFFFF (65535). The subsequent malloc succeeds and memcpy reads up to 65534 bytes from a 0-1 byte buffer, resulting in a heap out-of-bounds read. The attack vector involves a malicious or compromised LDAP KDB backend returning a krbExtraData attribute with bv_len < 2, triggering the underflow when the KDC or kadmind reads principal data.

CVSS 5.0 · Medium · EPSS 0.3% · Fix available

Published
Updated

Stack: system

Affected products and versions

  • red hat hardened images

    Versions
    • ≥ 1.22.2-8.hum1: Not affected (rpm)

    No fix published

  • red hat enterprise linux 10

    No fix published

  • red hat enterprise linux 6

    No fix published

  • red hat enterprise linux 7

    No fix published

  • red hat enterprise linux 8

    No fix published

  • red hat enterprise linux 9

    No fix published

  • red hat openshift container platform 4

    No fix published

  • krb5 Debian:12

    Versions
    • 1.20.1-2
    • 1.20.1-2+deb12u1
    • 1.20.1-2+deb12u2
    • 1.20.1-2+deb12u3
    • 1.20.1-2+deb12u4
    • 1.20.1-2+deb12u5
    • 1.20.1-2+loong64
    • 1.20.1-3
    • 1.20.1-4
    • 1.20.1-5
    • 1.20.1-5.1
    • 1.20.1-5.1~exp1
    • 1.20.1-6
    • 1.21.2-1
    • 1.21.3-1
    • 1.21.3-2
    • 1.21.3-3
    • 1.21.3-4
    • 1.21.3-5
    • 1.22.1-1
    • 1.22.1-2
    • 1.22.1-2.1
    • 1.22.1-3
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • krb5 Debian:13

    Versions
    • 1.21.3-5
    • 1.21.3-5+deb13u1
    • 1.22.1-1
    • 1.22.1-2
    • 1.22.1-2.1
    • 1.22.1-3
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • krb5 Debian:14

    Versions
    • 1.21.3-5
    • 1.22.1-1
    • 1.22.1-2
    • 1.22.1-2.1
    Affected ranges
    • ECOSYSTEM: < 1.22.1-3

    Update to 1.22.1-3

  • krb5 Ubuntu:Pro:14.04:LTS

    Versions
    • 1.10.1+dfsg-6.1ubuntu1
    • 1.11.3+dfsg-3ubuntu2
    • 1.12+dfsg-2ubuntu1
    • 1.12+dfsg-2ubuntu2
    • 1.12+dfsg-2ubuntu3
    • 1.12+dfsg-2ubuntu4
    • 1.12+dfsg-2ubuntu4.2
    • 1.12+dfsg-2ubuntu5
    • 1.12+dfsg-2ubuntu5.1
    • 1.12+dfsg-2ubuntu5.2
    • 1.12+dfsg-2ubuntu5.3
    • 1.12+dfsg-2ubuntu5.4
    • 1.12+dfsg-2ubuntu5.4+esm1
    • 1.12+dfsg-2ubuntu5.4+esm2
    • 1.12+dfsg-2ubuntu5.4+esm3
    • 1.12+dfsg-2ubuntu5.4+esm4
    • 1.12+dfsg-2ubuntu5.4+esm5
    • 1.12+dfsg-2ubuntu5.4+esm6
    • 1.12+dfsg-2ubuntu5.4+esm7
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • krb5 Ubuntu:Pro:16.04:LTS

    Versions
    • 1.13.2+dfsg-2
    • 1.13.2+dfsg-3
    • 1.13.2+dfsg-4
    • 1.13.2+dfsg-5
    • 1.13.2+dfsg-5ubuntu1
    • 1.13.2+dfsg-5ubuntu2
    • 1.13.2+dfsg-5ubuntu2.1
    • 1.13.2+dfsg-5ubuntu2.1+esm1
    • 1.13.2+dfsg-5ubuntu2.2
    • 1.13.2+dfsg-5ubuntu2.2+esm1
    • 1.13.2+dfsg-5ubuntu2.2+esm2
    • 1.13.2+dfsg-5ubuntu2.2+esm3
    • 1.13.2+dfsg-5ubuntu2.2+esm4
    • 1.13.2+dfsg-5ubuntu2.2+esm5
    • 1.13.2+dfsg-5ubuntu2.2+esm6
    • 1.13.2+dfsg-5ubuntu2.2+esm7
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • krb5 Ubuntu:Pro:18.04:LTS

    Versions
    • 1.15.1-2
    • 1.16-2
    • 1.16-2build1
    • 1.16-2ubuntu0.1
    • 1.16-2ubuntu0.1+esm1
    • 1.16-2ubuntu0.2
    • 1.16-2ubuntu0.3
    • 1.16-2ubuntu0.4
    • 1.16-2ubuntu0.4+esm1
    • 1.16-2ubuntu0.4+esm2
    • 1.16-2ubuntu0.4+esm3
    • 1.16-2ubuntu0.4+esm5
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • krb5 Ubuntu:20.04:LTS

    Versions
    • 1.17-6
    • 1.17-6ubuntu3
    • 1.17-6ubuntu4
    • 1.17-6ubuntu4.1
    • 1.17-6ubuntu4.2
    • 1.17-6ubuntu4.3
    • 1.17-6ubuntu4.4
    • 1.17-6ubuntu4.6
    • 1.17-6ubuntu4.7
    • 1.17-6ubuntu4.8
    • 1.17-6ubuntu4.9
    • 1.17-6ubuntu4.11
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • krb5 Ubuntu:22.04:LTS

    Versions
    • 1.18.3-6
    • 1.18.3-7
    • 1.19.2-0ubuntu1
    • 1.19.2-1
    • 1.19.2-2
    • 1.19.2-2ubuntu0.1
    • 1.19.2-2ubuntu0.2
    • 1.19.2-2ubuntu0.3
    • 1.19.2-2ubuntu0.4
    • 1.19.2-2ubuntu0.5
    • 1.19.2-2ubuntu0.6
    • 1.19.2-2ubuntu0.7
    Affected ranges
    • ECOSYSTEM: < 1.19.2-2ubuntu0.8

    Update to 1.19.2-2ubuntu0.8

  • krb5 Ubuntu:24.04:LTS

    Versions
    • 1.20.1-3ubuntu1
    • 1.20.1-5build1
    • 1.20.1-6ubuntu1
    • 1.20.1-6ubuntu2
    • 1.20.1-6ubuntu2.1
    • 1.20.1-6ubuntu2.2
    • 1.20.1-6ubuntu2.3
    • 1.20.1-6ubuntu2.4
    • 1.20.1-6ubuntu2.5
    • 1.20.1-6ubuntu2.6
    Affected ranges
    • ECOSYSTEM: < 1.20.1-6ubuntu2.7

    Update to 1.20.1-6ubuntu2.7

  • krb5 Ubuntu:25.10

    Versions
    • 1.21.3-4ubuntu2
    • 1.21.3-5ubuntu1
    • 1.21.3-5ubuntu2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • krb5 Ubuntu:26.04:LTS

    Versions
    • 1.21.3-5ubuntu2
    • 1.22.1-2
    • 1.22.1-2ubuntu2
    • 1.22.1-2ubuntu3
    • 1.22.1-2ubuntu4
    Affected ranges
    • ECOSYSTEM: < 1.22.1-2ubuntu4.1

    Update to 1.22.1-2ubuntu4.1

Original sources

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