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Fencer Intel
medium 6.8

CVE-2026-73313 json

XenForo < 2.3.13 MFA Bypass via Passkey TFA Provider

published 2mo ago modified last mo. also EUVD-2026-72784

cvss
6.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 48%
public exploits
0
none known

Summary

XenForo before 2.3.13 contains a multi-factor authentication bypass vulnerability in the passkey TFA provider that allows an authenticated attacker to complete login as another user by submitting their own registered passkey credential during the WebAuthn assertion step. The passkey verification path performs a global credential lookup without validating that the matched credential belongs to the user whose login is pending, enabling an attacker who knows a target account's password to sign the challenge with their own passkey and bypass multi-factor authentication on both public forum and ACP login paths.

Patch / fix

  • XenForo XenForo 2.3.13

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
last mo.

Exploit prediction

0.58% chance of exploitation in the next 30 days, higher than 48% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/BomboBombone/CVE-2026-73313 referenced PoC, tagged "exploit" by a source, unverified
  • bombobombone.github.io https://bombobombone.github.io/posts/cve-2026-73313/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 7.6 CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CNA 3.1 6.8 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
CNA 4.0 7.6 CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Affected products

  • XenForo XenForo

Classification

Weakness

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.