CVE-2026-91846
Fix: MISP/MISP@334d537CVE-2026-91846 is a CWE-639 vulnerability. O3 Security confirms whether CVE-2026-91846 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Affected versions of MISP allow a collection element to be created from a bare UUID without consistently checking whether the acting user is allowed to access the referenced object. The…
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-91846.
Description
Affected versions of MISP allow a collection element to be created from a bare UUID without consistently checking whether the acting user is allowed to access the referenced object.
The commit explains that collection elements themselves only store UUIDs, while the collection view later resolves those UUIDs into their underlying objects. Before this fix, the generic add() path could therefore persist a UUID for an Event or Galaxy Cluster that the caller could not normally read. The patch explicitly notes that this made collections a way to reference another organisation’s private data and had caused disclosure of organisation-only events in the beta collection view.
The fix centralizes authorization in __assertCanUseElements(). Event UUIDs are validated through Event::fetchSimpleEvent() under the current user’s ACL, while Galaxy Cluster UUIDs are checked through GalaxyCluster::fetchGalaxyClusters(). The check is applied both to the CRUD add() path and to addElementToCollection().
Version affected: ≤2.5.45
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2026-91846 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-91846 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-91846. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-91846 in your dependencies?
O3 detects CVE-2026-91846 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.