Skip to content
Heist/ feed
UnratedFix available

DEBIAN-CVE-2026-63387

Type: advisorySource: OSV1 source record

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has an off-by-one stack buffer overflow in evdns.c when dnsname_to_labels formats a name-bearing DNS record at the end of the 64 KB stack buffer allocated by evdns_server_request_format_response. The final-label check permits j plus label_len plus one to equal buf_len, after which the terminating null byte is written to buf[buf_len]. A crafted DNS server response containing PTR, CNAME, MX, NS, or SOA data can trigger the one-byte out-of-bounds write and crash or corrupt the process. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

Announced Source revision 1
Original source ↗

DEBIAN-CVE-2026-63387

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-2026-63387

libevent

Source reference: /affected/0/package/name

Affected versions
2.1.12-stable-8

Source reference: /affected/0/versions

Fixed versions
2.1.12-stable-8+deb12u1

Source reference: /affected/0/ranges

Prerequisites
Not stated in this record

libevent

Source reference: /affected/1/package/name

Affected versions
2.1.12-stable-10

Source reference: /affected/1/versions

Fixed versions
2.1.13-stable-1~deb13u1

Source reference: /affected/1/ranges

Prerequisites
Not stated in this record

libevent

Source reference: /affected/2/package/name

Affected versions
2.1.12-stable-10

Source reference: /affected/2/versions

2.1.13-stable-1~deb13u1

Source reference: /affected/2/versions

Fixed versions
2.1.13-stable-1

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"
          },
          {
            "fixed": "2.1.12-stable-8+deb12u1"
          }
        ]
      }
    ],
    "package": {
      "name": "libevent",
      "purl": "pkg:deb/debian/libevent?arch=source&distro=bookworm",
      "ecosystem": "Debian:12"
    },
    "versions": [
      "2.1.12-stable-8"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-63387.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "2.1.13-stable-1~deb13u1"
          }
        ]
      }
    ],
    "package": {
      "name": "libevent",
      "purl": "pkg:deb/debian/libevent?arch=source&distro=trixie",
      "ecosystem": "Debian:13"
    },
    "versions": [
      "2.1.12-stable-10"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-63387.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "2.1.13-stable-1"
          }
        ]
      }
    ],
    "package": {
      "name": "libevent",
      "purl": "pkg:deb/debian/libevent?arch=source&distro=forky",
      "ecosystem": "Debian:14"
    },
    "versions": [
      "2.1.12-stable-10",
      "2.1.13-stable-1~deb13u1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-63387.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  }
]

Publisher severity

No explicit severity was provided.

Event
#56054 · Revision 1
Added to Heist Feed
Publisher date
Read the original announcement