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DEBIAN-CVE-2026-9537

Type: advisorySource: OSV1 source record

Mojo::JWT versions before 1.02 for Perl verify HMAC signatures with a non-constant-time string comparison. The decode() method compares the supplied signature to the recomputed HMAC with Perl's eq operator, which stops at the first differing byte, so the comparison time varies with the number of matching leading bytes. A caller that decodes attacker supplied tokens leaks the expected signature through this timing variation, which can be aggregated over many requests to recover the signature and forge a token.

Announced Source revision 1
Original source ↗

DEBIAN-CVE-2026-9537

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-2026-9537

libmojo-jwt-perl

Source reference: /affected/0/package/name

Affected versions
0.09-1

Source reference: /affected/0/versions

1.01-1

Source reference: /affected/0/versions

1.02-1

Source reference: /affected/0/versions

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

libmojo-jwt-perl

Source reference: /affected/1/package/name

Affected versions
1.01-1

Source reference: /affected/1/versions

1.02-1

Source reference: /affected/1/versions

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

libmojo-jwt-perl

Source reference: /affected/2/package/name

Affected versions
1.01-1

Source reference: /affected/2/versions

Fixed versions
1.02-1

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"
          }
        ]
      }
    ],
    "package": {
      "name": "libmojo-jwt-perl",
      "purl": "pkg:deb/debian/libmojo-jwt-perl?arch=source&distro=bookworm",
      "ecosystem": "Debian:12"
    },
    "versions": [
      "0.09-1",
      "1.01-1",
      "1.02-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-9537.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          }
        ]
      }
    ],
    "package": {
      "name": "libmojo-jwt-perl",
      "purl": "pkg:deb/debian/libmojo-jwt-perl?arch=source&distro=trixie",
      "ecosystem": "Debian:13"
    },
    "versions": [
      "1.01-1",
      "1.02-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-9537.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "1.02-1"
          }
        ]
      }
    ],
    "package": {
      "name": "libmojo-jwt-perl",
      "purl": "pkg:deb/debian/libmojo-jwt-perl?arch=source&distro=forky",
      "ecosystem": "Debian:14"
    },
    "versions": [
      "1.01-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-9537.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  }
]

Publisher severity

No explicit severity was provided.

Event
#58589 · Revision 1
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Publisher date
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