CVE-2026-72889

Net::OAuth versions before 0.33 for Perl allow the sender to choose the signature algorithm in verify. verify resolves the signature method class from the signature_method parameter of the incoming message. signature_method is required on every request, so the algorithm used to check a signature is chosen by whoever sent it, and nothing lets the verifying party pin the method instead. When a message names HMAC-SHA1 or HMAC-SHA256, the key is derived from consumer_secret and token_secret rather than from the key the provider deployed. A provider deployed on RSA-SHA1 holds only the consumer public key, and RFC 5849 does not use consumer_secret for that method, so the required parameter is filled with a placeholder. A client that names HMAC-SHA1 instead has its signature checked against that placeholder, so a guessable one is enough to forge requests for any consumer key and token.
Configurations

No configuration.

History

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Information

Published : 2026-08-19 08:17

Updated : 2026-08-26 19:17


NVD link : CVE-2026-72889

Mitre link : CVE-2026-72889

CVE.ORG link : CVE-2026-72889


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Products Affected

No product.

CWE
CWE-347

Improper Verification of Cryptographic Signature

CWE-757

Selection of Less-Secure Algorithm During Negotiation ('Algorithm Downgrade')