{"id":"DEBIAN-CVE-2026-72889","details":"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.","modified":"2026-09-29T13:04:22.126249189Z","published":"2026-08-19T08:17:13.833Z","upstream":["CVE-2026-72889"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-72889"}],"affected":[{"package":{"name":"libnet-oauth-perl","ecosystem":"Debian:12","purl":"pkg:deb/debian/libnet-oauth-perl?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.28-4","0.30-1","0.31-1","0.31-2","0.32-1","0.33-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-72889.json"}},{"package":{"name":"libnet-oauth-perl","ecosystem":"Debian:13","purl":"pkg:deb/debian/libnet-oauth-perl?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.31-1","0.31-2","0.32-1","0.33-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-72889.json"}},{"package":{"name":"libnet-oauth-perl","ecosystem":"Debian:14","purl":"pkg:deb/debian/libnet-oauth-perl?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.33-1"}]}],"versions":["0.31-1","0.31-2","0.32-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-72889.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}