Symfony: Mailomat Mailer Webhook Parser Reads the HMAC Algorithm from the Request: Signature Algorithm Downgrade

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

• sensiolabs symfony7.2.0 and later · before 7.4.13
• sensiolabs symfony8.0.0 and later · before 8.0.13

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

• symfony mailomat-mailer

  • >= 7.2.0, < 7.4.12, >= 8.0.0-BETA1, < 8.0.13affected

• symfony symfony

  • >= 7.2.0, < 7.4.12, >= 8.0.0-BETA1, < 8.0.13affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Other highest-scoring records for the same primary product.

• CVE-2019-18889An issue was discovered in Symfony 3.4.0 through 3.4.34, 4.2.0 through 4.2.11, and 4.3.0 through 4.3.7.
  49Plan
• CVE-2018-14773An issue was discovered in Http Foundation in Symfony 2.7.0 through 2.7.48, 2.8.0 through 2.8.43, 3.3.0 through 3.3.17, 3.4.0 through 3.4.13
  43Plan
• CVE-2019-10910In Symfony before 2.7.51, 2.8.x before 2.8.50, 3.x before 3.4.26, 4.x before 4.1.12, and 4.2.x before 4.2.7, when service ids allow user inp
  41Plan
• CVE-2019-11325An issue was discovered in Symfony before 4.2.12 and 4.3.x before 4.3.8.
  40Plan
• CVE-2017-11365Certain Symfony products are affected by: Incorrect Access Control.
  40Plan
• CVE-2019-10913In Symfony before 2.7.51, 2.8.x before 2.8.50, 3.x before 3.4.26, 4.x before 4.1.12, and 4.2.x before 4.2.7, HTTP Methods provided as verbs
  40Plan

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Root cause

The verifier takes the algorithm to verify with from the token’s own header. Untrusted data ends up deciding its own verification rule.

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

1const claims = jwt.verify(token, publicKey);

1const claims = jwt.verify(token, publicKey, {2  algorithms: ["RS256"],3  issuer: "https://id.example.com",4  audience: "portal",5});

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.