{"id":"UBUNTU-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":"2026-09-02T16:26:09Z","published":"2026-08-19T08:17:00Z","upstream":["CVE-2026-72889"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-72889"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-72889"},{"type":"REPORT","url":"https://lists.security.metacpan.org/cve-announce/msg/42818761/"},{"type":"REPORT","url":"https://github.com/vurtdev/Net-OAuth/security/advisories/GHSA-c8rm-g5cm-4pf5"},{"type":"REPORT","url":"https://datatracker.ietf.org/doc/html/rfc5849#section-3.4.2"},{"type":"REPORT","url":"https://datatracker.ietf.org/doc/html/rfc5849#section-3.4.3"},{"type":"REPORT","url":"https://github.com/vurtdev/Net-OAuth/commit/c467adf45c8d77ac4b92ad78b3eebf949252ba7f.patch"},{"type":"REPORT","url":"https://metacpan.org/release/RRWO/Net-OAuth-0.33/changes"}],"affected":[{"package":{"name":"libnet-oauth-perl","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/libnet-oauth-perl?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.28-2"],"ecosystem_specific":{"binaries":[{"binary_name":"libnet-oauth-perl","binary_version":"0.28-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-72889.json"}},{"package":{"name":"libnet-oauth-perl","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/libnet-oauth-perl?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.28-2"],"ecosystem_specific":{"binaries":[{"binary_name":"libnet-oauth-perl","binary_version":"0.28-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-72889.json"}},{"package":{"name":"libnet-oauth-perl","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/libnet-oauth-perl?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.28-3"],"ecosystem_specific":{"binaries":[{"binary_version":"0.28-3","binary_name":"libnet-oauth-perl"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-72889.json"}},{"package":{"name":"libnet-oauth-perl","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/libnet-oauth-perl?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.28-3"],"ecosystem_specific":{"binaries":[{"binary_version":"0.28-3","binary_name":"libnet-oauth-perl"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-72889.json"}},{"package":{"name":"libnet-oauth-perl","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/libnet-oauth-perl?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.28-4"],"ecosystem_specific":{"binaries":[{"binary_version":"0.28-4","binary_name":"libnet-oauth-perl"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-72889.json"}},{"package":{"name":"libnet-oauth-perl","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/libnet-oauth-perl?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.31-1"],"ecosystem_specific":{"binaries":[{"binary_version":"0.31-1","binary_name":"libnet-oauth-perl"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-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"},{"type":"Ubuntu","score":"medium"}]}