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DEBIAN-CVE-2026-11850

Type: advisorySource: OSV1 source record

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.

Announced Source revision 1
Original source ↗

DEBIAN-CVE-2026-11850

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: osv:DEBIAN-CVE-2026-11850

krb5

Source reference: /affected/0/package/name

Affected versions
1.20.1-2

Source reference: /affected/0/versions

1.20.1-2+deb12u1

Source reference: /affected/0/versions

1.20.1-2+deb12u2

Source reference: /affected/0/versions

1.20.1-2+deb12u3

Source reference: /affected/0/versions

1.20.1-2+deb12u4

Source reference: /affected/0/versions

1.20.1-2+deb12u5

Source reference: /affected/0/versions

1.20.1-2+loong64

Source reference: /affected/0/versions

1.20.1-3

Source reference: /affected/0/versions

1.20.1-4

Source reference: /affected/0/versions

1.20.1-5

Source reference: /affected/0/versions

1.20.1-5.1

Source reference: /affected/0/versions

1.20.1-5.1~exp1

Source reference: /affected/0/versions

1.20.1-6

Source reference: /affected/0/versions

1.21.2-1

Source reference: /affected/0/versions

1.21.3-1

Source reference: /affected/0/versions

1.21.3-2

Source reference: /affected/0/versions

1.21.3-3

Source reference: /affected/0/versions

1.21.3-4

Source reference: /affected/0/versions

1.21.3-5

Source reference: /affected/0/versions

1.22.1-1

Source reference: /affected/0/versions

1.22.1-2

Source reference: /affected/0/versions

1.22.1-2.1

Source reference: /affected/0/versions

1.22.1-3

Source reference: /affected/0/versions

Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

krb5

Source reference: /affected/1/package/name

Affected versions
1.21.3-5

Source reference: /affected/1/versions

1.21.3-5+deb13u1

Source reference: /affected/1/versions

1.22.1-1

Source reference: /affected/1/versions

1.22.1-2

Source reference: /affected/1/versions

1.22.1-2.1

Source reference: /affected/1/versions

1.22.1-3

Source reference: /affected/1/versions

Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

krb5

Source reference: /affected/2/package/name

Affected versions
1.21.3-5

Source reference: /affected/2/versions

1.22.1-1

Source reference: /affected/2/versions

1.22.1-2

Source reference: /affected/2/versions

1.22.1-2.1

Source reference: /affected/2/versions

Fixed versions
1.22.1-3

Source reference: /affected/2/ranges

Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          }
        ]
      }
    ],
    "package": {
      "name": "krb5",
      "purl": "pkg:deb/debian/krb5?arch=source&distro=bookworm",
      "ecosystem": "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"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-11850.json"
    },
    "ecosystem_specific": {
      "urgency": "unimportant"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          }
        ]
      }
    ],
    "package": {
      "name": "krb5",
      "purl": "pkg:deb/debian/krb5?arch=source&distro=trixie",
      "ecosystem": "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"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-11850.json"
    },
    "ecosystem_specific": {
      "urgency": "unimportant"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "1.22.1-3"
          }
        ]
      }
    ],
    "package": {
      "name": "krb5",
      "purl": "pkg:deb/debian/krb5?arch=source&distro=forky",
      "ecosystem": "Debian:14"
    },
    "versions": [
      "1.21.3-5",
      "1.22.1-1",
      "1.22.1-2",
      "1.22.1-2.1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-11850.json"
    },
    "ecosystem_specific": {
      "urgency": "unimportant"
    }
  }
]

Publisher severity

No explicit severity was provided.

Event
#55480 · Revision 1
Added to Heist Feed
Publisher date
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