Session hijacking via unrotated overwritten cookie token
Published Mar 12, 2025 · Updated Mar 12, 2025
Session hijacking in Flarum before 1.8.10 allows remote attackers to replace a victim's session token through a sibling-domain cookie. The RememberFromCookie middleware writes a differing cookie token into access_token without invalidating the existing session or rotating its token. Exploitation requires control of a direct child subdomain, a parent domain outside the Public Suffix List, and victim interaction; the advisory states browser protections prevented exploitation as described.
Summary
What happened
Session hijacking in Flarum before 1.8.10 allows remote attackers to replace a victim's session token through a sibling-domain cookie. The RememberFromCookie middleware writes a differing cookie token into access_token without invalidating the existing session or rotating its token. Exploitation requires control of a direct child subdomain, a parent domain outside the Public Suffix List, and victim interaction; the advisory states browser protections prevented exploitation as described.
The record
- CVE
- CVE-2025-27794
- Published
- Mar 12, 2025
- Updated
- Mar 12, 2025
- Vendor
- Flarum
- Product
- Flarum
- Classifications
- CWE-74, T1550.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 12, 2025CVE publishedPublication date reported by the CVE source.
- Mar 12, 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.
- Affected versionversion=< 1.8.10
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
- Deno sibling-domain cookie overwrite proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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