CVE-2025-27794: Flarum Vulnerable to Session Hijacking via Authoritative Subdomain Cookie Overwrite

CVE-2025-27794 · Severity: low · CVSS 3.1 · Published 2025-03-12

Flarum Vulnerable to Session Hijacking via Authoritative Subdomain Cookie Overwrite

Technologies: flarum/core (Packagist), flarum/framework (Packagist). Vendors: Packagist.

Quick answers

Is CVE-2025-27794 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2025-27794 being exploited in the wild.
How severe is CVE-2025-27794?
Low severity, with a CVSS score of 3.1, published 12 March 2025.
Which products and versions are affected?
flarum/core (Packagist) ECOSYSTEM:introduced=0,fixed=1.8.10; flarum/framework (Packagist) ECOSYSTEM:introduced=0,fixed=1.8.10.
Is there a fix for CVE-2025-27794?
Yes. flarum/core (Packagist): upgrade to 1.8.10 or later; flarum/framework (Packagist): upgrade to 1.8.10 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2025-27794?
Check whether you run flarum/core (Packagist) or flarum/framework (Packagist) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • flarum/core (Packagist): upgrade to 1.8.10 or later
    composer require flarum/core:^1.8.10
  • flarum/framework (Packagist): upgrade to 1.8.10 or later
    composer require flarum/framework:^1.8.10

Affected products

  • flarum/core (Packagist) ECOSYSTEM:introduced=0,fixed=1.8.10
  • flarum/framework (Packagist) ECOSYSTEM:introduced=0,fixed=1.8.10

Identifiers

  • CVE-2025-27794
  • GHSA-hg9j-64wp-m9px

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