CVE-2026-73312Network attack vector

Persistent account access via refresh token replay

Published Sep 8, 2026 · Updated Sep 9, 2026

Authentication bypass in XenForo before 2.3.13 allows remote attackers to retain account access by replaying a captured refresh token. The refresh-token exchange path fails to mark a refresh token as consumed when its parent access token has expired, so the same token can mint multiple independent token pairs. Possession of a valid refresh token and expiration of its parent access token are required; successful replay preserves account access for the refresh token's lifetime.

CVSS severity9.1
Critical
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in XenForo before 2.3.13 allows remote attackers to retain account access by replaying a captured refresh token. The refresh-token exchange path fails to mark a refresh token as consumed when its parent access token has expired, so the same token can mint multiple independent token pairs. Possession of a valid refresh token and expiration of its parent access token are required; successful replay preserves account access for the refresh token's lifetime.

The record

CVE
CVE-2026-73312
Published
Sep 8, 2026
Updated
Sep 9, 2026
Vendor
XenForo Ltd.
Product
XenForo
Classifications
CWE-294, T1550.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <2.3.13

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

XenForo Ltd. · XenForoversion=0 <2.3.13

Published CVSS scores

9.1VulnCheckCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
7.4VulnCheckCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-294Authentication Bypass by Capture-replay
T1550.001Use Alternate Authentication Material: Application Access Token

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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