MEDIUMVulnerability
CVE-2026-73321
XenForo before 2.3.13 contains an uncontrolled recursion vulnerability in the BBCode parser that allows authenticated attackers to cause persistent denial of service by submitting a post with deeply nested BBCode tags. Attackers can craft a single malicious post with sufficient nesting depth to exceed PHP's stack limit, causing fatal errors that repeatedly terminate PHP-FPM workers for all visitors rendering the affected thread.
Properties
- severity
- MEDIUM
- score
- 6.5
- cve_id
- CVE-2026-73321
- signal_observed_at
- 2026-09-16T21:37:07+00:00
- vector
- CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- published_at
- 2026-09-08T14:17:26.617
- last_modified
- 2026-09-11T20:30:18.293
Related Entities (3)
HAS_WEAKNESS (1)
→[Weakness]Uncontrolled Recursion
DESCRIBED_BY (1)
→[Source]NVD
AFFECTS_PRODUCT (1)
→[Product]
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