Quick answers
- Is CVE-2026-86351 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-86351 being exploited in the wild.
- How severe is CVE-2026-86351?
- Medium severity, with a CVSS score of 6.1, published 7 September 2026.
- Which products and versions are affected?
- Misp ≤2.5.45.
- Is there a fix for CVE-2026-86351?
- A patch was published on 2026-08-26: Fix committed to repository Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-86351 attacked?
- It is attacked over the network, in a web application.
- Am I affected by CVE-2026-86351?
- Check whether you run Misp 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 an open redirect in the homepage setting validation. MISP validated user-configurable homepage paths by checking only whether they began with a forward slash (/), which is insufficient because protocol-relative URLs like //attacker.example also start with / but resolve to an external origin in browsers. The vulnerable homepage value is stored in user settings and later retrieved by post-login routing logic, which emits the unvalidated path to the Location HTTP header. The fix implements a comprehensive InternalRedirectValidator that rejects URLs containing a host, scheme, userinfo, unsafe leading sequences (//, /\), malformed URLs, and control characters, with revalidation on read to catch legacy unsafe values.
Affected products
- MISP MISP ≤2.5.45
Timeline
- 2026-09-07: disclosed: Published on NVD
- 2026-08-26: patched: Fix committed to repository