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UBUNTU-CVE-2026-48525

Type: advisorySource: OSV1 source record

PyJWT is a JSON Web Token implementation in Python. From 2.8.0 to 2.12.1, when verifying detached JWS tokens using the unencoded-payload option ("b64": false, RFC 7797), PyJWT performs Base64URL decoding of the compact-serialization payload segment before enforcing the detached-payload rules. For b64=false, PyJWT later discards that decoded payload and replaces it with the caller-provided detached_payload. In practice, this turns the middle segment into an attacker-controlled “work amplifier”: a remote client can supply an arbitrarily large Base64URL payload segment that forces CPU work + memory allocations even if the signature is invalid. This creates an unauthenticated DoS vector against any endpoint that verifies detached JWS using PyJWT. This vulnerability is fixed in 2.13.0.

Announced Source revision 1
Original source ↗

UBUNTU-CVE-2026-48525

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:UBUNTU-CVE-2026-48525

pyjwt

Source reference: /affected/0/package/name

Affected versions
2.7.0-1

Source reference: /affected/0/versions

2.7.0-1ubuntu0.1

Source reference: /affected/0/versions

Fixed versions
2.7.0-1ubuntu0.2

Source reference: /affected/0/ranges

Prerequisites
Not stated in this record

pyjwt

Source reference: /affected/1/package/name

Affected versions
2.10.1-2

Source reference: /affected/1/versions

2.10.1-2ubuntu0.1

Source reference: /affected/1/versions

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

pyjwt

Source reference: /affected/2/package/name

Affected versions
2.10.1-2

Source reference: /affected/2/versions

2.10.1-3

Source reference: /affected/2/versions

2.10.1-3build1

Source reference: /affected/2/versions

2.10.1-4

Source reference: /affected/2/versions

2.10.1-4ubuntu1

Source reference: /affected/2/versions

Fixed versions
2.10.1-4ubuntu1.1

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": "2.7.0-1ubuntu0.2"
          }
        ]
      }
    ],
    "package": {
      "name": "pyjwt",
      "purl": "pkg:deb/ubuntu/pyjwt?arch=source&distro=noble",
      "ecosystem": "Ubuntu:24.04:LTS"
    },
    "versions": [
      "2.7.0-1",
      "2.7.0-1ubuntu0.1"
    ],
    "database_specific": {
      "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48525.json"
    },
    "ecosystem_specific": {
      "binaries": [
        {
          "binary_name": "python3-jwt",
          "binary_version": "2.7.0-1ubuntu0.2"
        }
      ],
      "availability": "No subscription required"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          }
        ]
      }
    ],
    "package": {
      "name": "pyjwt",
      "purl": "pkg:deb/ubuntu/pyjwt?arch=source&distro=questing",
      "ecosystem": "Ubuntu:25.10"
    },
    "versions": [
      "2.10.1-2",
      "2.10.1-2ubuntu0.1"
    ],
    "database_specific": {
      "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48525.json"
    },
    "ecosystem_specific": {
      "binaries": [
        {
          "binary_name": "python3-jwt",
          "binary_version": "2.10.1-2ubuntu0.1"
        }
      ]
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "2.10.1-4ubuntu1.1"
          }
        ]
      }
    ],
    "package": {
      "name": "pyjwt",
      "purl": "pkg:deb/ubuntu/pyjwt?arch=source&distro=resolute",
      "ecosystem": "Ubuntu:26.04:LTS"
    },
    "versions": [
      "2.10.1-2",
      "2.10.1-3",
      "2.10.1-3build1",
      "2.10.1-4",
      "2.10.1-4ubuntu1"
    ],
    "database_specific": {
      "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-48525.json"
    },
    "ecosystem_specific": {
      "binaries": [
        {
          "binary_name": "python3-jwt",
          "binary_version": "2.10.1-4ubuntu1.1"
        }
      ],
      "availability": "No subscription required"
    }
  }
]

Publisher severity

No explicit severity was provided.

Event
#22395 · Revision 1
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Publisher date
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