CVE-2026-72889
Received
Received - Intake
Signature Forgery in Net::OAuth Perl Library
Vulnerability report for CVE-2026-72889, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-08-19
Last updated on: 2026-08-19
Assigner: CPANSec
Description
Description
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.
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| vurtdev | net_oauth | to 0.32 (inc) |
| vurtdev | net_oauth | 0.31 |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-757 | A protocol or its implementation supports interaction between multiple actors and allows those actors to negotiate which algorithm should be used as a protection mechanism such as encryption or authentication, but it does not select the strongest algorithm that is available to both parties. |
| CWE-347 | The product does not verify, or incorrectly verifies, the cryptographic signature for data. |
