CVE-2026-72889

libnet-oauth-perl: Net::OAuth versions before 0.33 for Perl allow the sender to choose the signature algorithm in verify

CVE-2026-72889 is fixed in libnet-oauth-perl on 1 platform by DEBIAN-CVE-2026-72889 (version 0.33-1), released August 29, 2026. It is not reported as exploited. Patch Radar priority: Urgent.

Urgent
CVSS
9.8
critical
Exploitation
None reported
No vendor assessment
CISA KEV
Not listed
Not in the Known Exploited Vulnerabilities catalog
EPSS
0.0045
39th percentile

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.

Where it's fixed

ProductFixed inFixReleased
Linux
libnet-oauth-perl · Debian 14 0.33-1 DEBIAN-CVE-2026-72889 Aug 29, 2026

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