CVE-2025-53102Network attack vector

Authentication replay via retained WebAuthn challenge

Published Jul 29, 2025 · Updated Jul 29, 2025

Session fixation in Discourse before 3.4.7 and 3.5.0.beta1 through 3.5.0.beta.7 allows remote attackers to reuse a WebAuthn challenge. The WebAuthn authentication service left the signed challenge in SecureSession after successful validation instead of deleting or expiring it. The condition exists only when physical security-key 2FA is used, and the published impact is limited to data confidentiality.

CVSS severity8.2
High
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Session fixation in Discourse before 3.4.7 and 3.5.0.beta1 through 3.5.0.beta.7 allows remote attackers to reuse a WebAuthn challenge. The WebAuthn authentication service left the signed challenge in SecureSession after successful validation instead of deleting or expiring it. The condition exists only when physical security-key 2FA is used, and the published impact is limited to data confidentiality.

The record

CVE
CVE-2025-53102
Published
Jul 29, 2025
Updated
Jul 29, 2025
Vendor
Discourse
Product
Discourse
Classifications
CWE-384, T1550
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 29, 2025CVE publishedPublication date reported by the CVE source.
  2. Jul 29, 2025Record 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=< 3.4.7
  2. Affected versionversion=>= 3.5.0.beta1, < 3.5.0.beta.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Discourse · Discourseversion=< 3.4.7; version=>= 3.5.0.beta1, < 3.5.0.beta.8

Published CVSS scores

8.2GitHub CNACVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA: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-384Session Fixation
T1550Use Alternate Authentication Material

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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