CVE-2026-72887: Net-OAuth (Perl module) · Algorithm Downgrade
Affects Net-OAuth (Perl module)Source CVE Database V5
Not known to be exploited · CVSS 9.8 Critical : upgrade to 0.32 as a priority.
Data as of 13 Nov 2026, 23:54 UTC
- EPSS
- 0.7% chance of exploitation in 30 days – higher than 54% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 0.32
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 16 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.
What to do
Upgrade Net-OAuth (Perl module) to 0.32.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
CPANNet-OAuthpkg:cpan/Net-OAuthOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
If you cannot patch yet, users should avoid using vulnerable versions of Net::OAuth::Client and consider implementing additional checks to ensure the use of OAuth 1.0a, such as verifying the presence of oauth_callback_confirmed and oauth_verifier parameters. Monitoring for updates from the vendor or CPAN security advisories is recommended.
Description
Net::OAuth::Client versions before 0.32 for Perl allow a silent downgrade from OAuth 1.0a to OAuth 1.0 during the get_request_token process. This downgrade occurs when the service provider omits the oauth_callback_confirmed parameter, causing the client to revert to OAuth 1.0 without warning or exception. The downgrade results in the omission of the oauth_verifier parameter in the access token request, enabling an OAuth 1.0 session fixation attack. An attacker can obtain a request token, have the victim authorize it, and then complete the token exchange to link the victim's account to a session controlled by the attacker. No attacker action is required to initiate the downgrade other than the provider not confirming the callback.
References
- github.com/vurtdev/Net-OAuth/security/advisories/GHSA-jh72-4qq2-8j6g (opens in a new tab)
- metacpan.org/release/RRWO/Net-OAuth-0.32/changes (opens in a new tab)
- github.com/vurtdev/Net-OAuth/commit/fd505dac1988723ed96721657663f2e4ac731644.patch (opens in a new tab)
- datatracker.ietf.org/doc/html/rfc5849 (opens in a new tab)
- datatracker.ietf.org/doc/html/rfc5849 (opens in a new tab)
- openwall.com/lists/oss-security/2026/08/16/3 (opens in a new tab)