CVE-2026-86342: Affected versions of MISP contain improper authorization checks in the freetext feed preview functionality.

Affected versions of MISP contain improper authorization checks in the freetext feed preview functionality.

Affected versions of MISP contain improper authorization checks in the freetext feed preview functionality. The preview performed correlation lookups against attributes from events without applying the requesting user's ACL, allowing restricted event correlations and associated event information to be exposed to users who could not otherwise access those events. The vulnerable queries were scoped only by attribute values and deletion status rather than MISP's event, organization, sharing-group, attribute, and object-level access controls. The same preview functionality also returned cross-feed correlation information without properly restricting the feed list to feeds visible to the caller. This exposed metadata for feeds that were not marked lookup_visible; one affected response additionally included the configured feed URL even though that value was not required by the feature. The fixes apply the caller's ACL to attribute correlation searches, remove feed URLs from correlation results, restrict cross-feed results according to feed visibility, and correct host-organization ID comparison so the authorization rules are applied consistently. Version affected: ≤2.5.45

Description from the National Vulnerability Database, published by 5a6e4751-2f3f-4070-9419-94fb35b644e8

What it means for a small business

If your business uses MISP, install the vendor's update. If you're not sure whether you use it, ask whoever manages your computers.

How likely is an attack? The Exploit Prediction Scoring System, run by FIRST (the global association of security response teams), puts the odds of this one being exploited in the next 30 days at 0.34%, higher than 27% of CVEs. That’s low, but low isn’t zero, and the odds jump the day someone publishes an exploit. Scored October 29, 2026, updated daily.

Check your own setup

Website check: reads what your site runs from the outside (WordPress version, plugins it can see, old server software) and matches it against this database.
Server check: what your web server says about itself, and whether that version has known flaws.

Sources

Part of the Huttenlocher Technologies vulnerability database, refreshed twice a day from CISA and the NVD. The title, category and plain-language guidance are ours; check the linked record before acting on a detail. This is general guidance, not a review of your systems.

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