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Fencer Vulns
critical 9.1

CVE-2026-78655 json

Punk::Plugin::TOTP versions before 0.05 for Perl allow the second-factor attempt limit to be reset by replaying an earlier session cookie because the challenge route counts failures in the session

published 2026-08-25 2 mo ago modified 2026-08-26 2 mo ago also EUVD-2026-66120

cvss
9.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 42%
public exploits
0
none known

Summary

Punk::Plugin::TOTP versions before 0.05 for Perl allow the second-factor attempt limit to be reset by replaying an earlier session cookie because the challenge route counts failures in the session.

The POST handler on challenge_path keeps the failure count as tries inside the totp_pending record in the session, raising it on each rejected code and deleting the pending record once it reaches attempts, five by default. Punk::Session carries the session in a signed cookie unless the application declares a store, and keeps no server-side record, so an earlier value of the same session stays valid until the expiry stamped inside it. A client that saves the cookie before its failed attempts and presents it again gets the pending record back with its counter, and the limit never fires. The replayed record is accepted while its own expiry, pending_ttl seconds from the challenge and 300 by default, has not passed.

Sessions declared with a store are not affected: the pending record and its counter then live server-side.

The attempt limit does not bound guessing of the second factor, which is left to the per-address rate limit the plugin registers on the same path, 30 requests per 60 seconds.

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
2 mo ago

Exploit prediction

0.50% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Classification

Weakness
  • CWE-307 Improper Restriction of Excessive Authentication Attempts
  • CWE-642 External Control of Critical State Data

References

Sources

Fencer Vulns 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.