CVE-2026-86351 (GCVE-0-2026-86351)
Vulnerability from cvelistv5
Published
2026-09-07 09:59
Modified
2026-09-08 14:49
Severity ?
5.1 (Medium) - CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N
CWE
  • CWE-601 - URL Redirection to Untrusted Site ('Open Redirect')
  • CWE-20 - Improper Input Validation
Summary
Affected versions of MISP validate the user-configurable homepage by checking only whether the supplied path begins with /. That check is insufficient because protocol-relative URLs such as //attacker.example also begin with / but resolve to an external origin in browsers. The vulnerable homepage value can be stored as a user setting and later used by the post-login routing logic. The commit explicitly identifies //attacker.example as a payload that passed validation and was emitted to the Location header after login. The fix introduces a shared InternalRedirectValidator that rejects URLs containing a host, scheme, userinfo, unsafe leading // or /\, malformed URLs, and control characters. It also revalidates homepage settings on read so legacy or internally written unsafe values cannot bypass the new storage-time validation. Version affected: ≤2.5.45
References
Impacted products
Vendor Product Version
MISP MISP Version: 0   ≤ 2.5.45
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