Quick answers
- Is CVE-2026-76877 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-76877 being exploited in the wild.
- How severe is CVE-2026-76877?
- High severity, with a CVSS score of 8.1, published 10 November 2026.
- Which products and versions are affected?
- WPML Multilingual CMS up to and including 4.9.7.
- Is there a fix for CVE-2026-76877?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-76877 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-76877?
- Check whether you run WPML Multilingual CMS 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.
Technical details
The vulnerability is a race condition in the `process_iframe_request` function's language-per-domain SSO handler. The function generates cross-domain sign-in tokens via `wp_create_nonce()` on the logout landing page when session tokens are empty, producing predictable anonymous nonces. An attacker can derive the same token by triggering the logout flow independently and submit it with a forged sign-in status to a secondary domain before the legitimate sign-out iframe completes, within a 60-second race window.
Affected products
- WPML Multilingual CMS up to and including 4.9.7
Timeline
- 2026-11-10: disclosed