CVE-2023-29020Network attack vector

CSRF bypass via pre-login token preservation

Published Apr 21, 2023 · Updated Feb 4, 2025

CSRF token fixation in @fastify/passport before 1.1.0 and 2.0.0 through 2.2.0 allows remote attackers to forge authenticated requests. The authentication path preserves the session's _csrf value across login, leaving a token generated for the attacker's pre-session valid afterward. Exploitation requires a same-site attacker to plant that pre-session cookie and the victim to authenticate before a forged state-changing request is submitted.

CVSS severity6.5
Medium
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

CSRF token fixation in @fastify/passport before 1.1.0 and 2.0.0 through 2.2.0 allows remote attackers to forge authenticated requests. The authentication path preserves the session's _csrf value across login, leaving a token generated for the attacker's pre-session valid afterward. Exploitation requires a same-site attacker to plant that pre-session cookie and the victim to authenticate before a forged state-changing request is submitted.

The record

CVE
CVE-2023-29020
Published
Apr 21, 2023
Updated
Feb 4, 2025
Vendor
Fastify
Product
@fastify/passport
Classifications
CWE-384, CWE-352, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 21, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 4, 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=< 1.1.0
  2. Affected versionversion=>= 2.0.0, < 2.3.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Fastify · @fastify/passportversion=< 1.1.0; version=>= 2.0.0, < 2.3.0

Published CVSS scores

6.5GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
6.5NISTCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/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-384Session Fixation
CWE-352Cross-Site Request Forgery (CSRF)
T1190Exploit Public-Facing Application

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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