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Fencer Intel
critical 9.8

CVE-2026-72889 json

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

published 2mo ago modified 15d ago also EUVD-2026-62347 , GHSA-c8rm-g5cm-4pf5

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository vurtdev/Net-OAuth. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 39%
public exploits
0
none known

Summary

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.

Patch / fix

  • libnet-oauth-perl Debian 14 0.33-1

debian advisories DEBIAN-CVE-2026-72889

  • perl-Net-OAuth openSUSE Tumbleweed 0.330.0-1.1

opensuse advisories openSUSE-SU-2026:11551-1

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-72889 updated cvss 9.8

Net-OAuth: Net::OAuth: Authentication bypass via chosen signature algorithm

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
2mo ago

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CISA ADP 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Classification

Weakness
  • CWE-347 Improper Verification of Cryptographic Signature
  • CWE-757 Selection of Less-Secure Algorithm During Negotiation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of vurtdev/Net-OAuth published their own advisory on GitHub. Reviewed sources take precedence over it.