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DEBIAN-CVE-2026-57076

Type: advisorySource: OSV1 source record

YAML::Syck versions before 1.47 for Perl allow a heap use-after-free via an anchor name reused as an anchors-table key in syck_hdlr_add_anchor. In the bundled libsyck an anchor name allocated by syck_strndup is stored both as node->anchor, freed when the node is freed, and as the key in the parser's anchors table. Freeing the node frees the shared key, and a later anchor redefinition makes st_delete compare against the freed key, so st_strcmp reads freed heap memory. Anchors are a standard YAML feature and need no special flags, so this is reached on the default Load path. Any caller that runs Load or LoadFile on an untrusted document that redefines an anchor reaches the read of freed memory.

Announced Source revision 1
Original source ↗

DEBIAN-CVE-2026-57076

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-2026-57076

libyaml-syck-perl

Source reference: /affected/0/package/name

Affected versions
1.34-2

Source reference: /affected/0/versions

1.34-2+deb12u1

Source reference: /affected/0/versions

1.34-2+deb12u2

Source reference: /affected/0/versions

Fixed versions
1.34-2+deb12u3

Source reference: /affected/0/ranges

Prerequisites
Not stated in this record

libyaml-syck-perl

Source reference: /affected/1/package/name

Affected versions
1.34-2

Source reference: /affected/1/versions

1.34-2+deb13u1

Source reference: /affected/1/versions

1.34-2+deb13u2

Source reference: /affected/1/versions

Fixed versions
1.34-2+deb13u3

Source reference: /affected/1/ranges

Prerequisites
Not stated in this record

libyaml-syck-perl

Source reference: /affected/2/package/name

Affected versions
1.34-2

Source reference: /affected/2/versions

1.34-3

Source reference: /affected/2/versions

1.34-4

Source reference: /affected/2/versions

1.36-1

Source reference: /affected/2/versions

1.36-2

Source reference: /affected/2/versions

1.36-3

Source reference: /affected/2/versions

Fixed versions
1.47-1

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": "1.34-2+deb12u3"
          }
        ]
      }
    ],
    "package": {
      "name": "libyaml-syck-perl",
      "purl": "pkg:deb/debian/libyaml-syck-perl?arch=source&distro=bookworm",
      "ecosystem": "Debian:12"
    },
    "versions": [
      "1.34-2",
      "1.34-2+deb12u1",
      "1.34-2+deb12u2"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-57076.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "1.34-2+deb13u3"
          }
        ]
      }
    ],
    "package": {
      "name": "libyaml-syck-perl",
      "purl": "pkg:deb/debian/libyaml-syck-perl?arch=source&distro=trixie",
      "ecosystem": "Debian:13"
    },
    "versions": [
      "1.34-2",
      "1.34-2+deb13u1",
      "1.34-2+deb13u2"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-57076.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "1.47-1"
          }
        ]
      }
    ],
    "package": {
      "name": "libyaml-syck-perl",
      "purl": "pkg:deb/debian/libyaml-syck-perl?arch=source&distro=forky",
      "ecosystem": "Debian:14"
    },
    "versions": [
      "1.34-2",
      "1.34-3",
      "1.34-4",
      "1.36-1",
      "1.36-2",
      "1.36-3"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-57076.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  }
]

Publisher severity

No explicit severity was provided.

Event
#57936 · Revision 1
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Publisher date
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