CVE-2026-95659: MISP Reflected XSS via Unvalidated Object Type in AnalystData Overmind Thread

Is it exploited?

Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of 29 Oct 2026. If CISA adds it, this page shows it as known exploited.

How likely is exploitation in the next 30 days?

0.4%

EPSS score, percentile 33 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?

4.8 Medium

CVSS v4.0 base score, given by the CNA

What should I do?

The fix introduces two layers of defense. Full textSolution from the CVE record.

CISA has set no required action, because the vulnerability is not in KEV.

Advisories and patches (1)

Which versions are affected?

Affected

• before 2.5.47

Versions by product

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026; CVE List, as of 29 Oct 2026. About the data.

What to do

Solution (from the CVE record)

The fix introduces two layers of defense. First, the viewForObject action now validates the object_type parameter against the AnalystData::valid_targets whitelist and rejects any value not in that list with a NotFoundException, preventing arbitrary strings from reaching the view layer. Second, the two output sinks in the Overmind thread.ctp template now apply the h() HTML-encoding function to the object type before interpolation into translated strings, ensuring that even if a valid type were to contain special characters, it would be rendered as inert text rather than executable markup.

Advisories and patches

• Security patch (Patch)

This summary is based on the CVE record as of 29 Oct 2026. Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

As listed in the CVE record.

Versions not listed are: unaffected.

Source: CVE List, as of 29 Oct 2026. About the data.

About this vulnerability

MISP contains a reflected cross-site scripting (XSS) vulnerability in the AnalystDataController::viewForObject action. The method accepted a parent object type parameter from the URL without validation and passed it to the Overmind-themed AnalystData thread view element, where it was interpolated into two translated strings and rendered into the HTML response without output encoding. An authentic…

Summary: CVE record, as of 29 Oct 2026.

• CISA has not added CVE-2026-95659 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
• The CVE record was published on 22 Sep 2026.
• The CVE record carries a CVSS v4.0 base score of 4.8 (Medium), given by its CNA.
• FIRST's EPSS model puts the probability of exploitation in the next 30 days at 0.4% (percentile 33), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
• CISA's SSVC assessment in the CVE record: exploitation none, automatable no, technical impact partial.
• The credits in the CVE record name Anthropic (Claude) as finder.

Source: CISA KEV 2026.10.29, as of 29 Oct 2026; CVE List, as of 29 Oct 2026; FIRST EPSS, as of 29 Oct 2026. About the data.

Description

MISP Reflected XSS via Unvalidated Object Type in AnalystData Overmind Thread

MISP contains a reflected cross-site scripting (XSS) vulnerability in the AnalystDataController::viewForObject action. The method accepted a parent object type parameter from the URL without validation and passed it to the Overmind-themed AnalystData thread view element, where it was interpolated into two translated strings and rendered into the HTML response without output encoding. An authenticated attacker who can induce a victim to navigate to a crafted URL can inject arbitrary JavaScript that executes in the victim's browser within the MISP application context. This may allow the attacker to read session data, manipulate the page, or perform actions on behalf of the victim.  The vulnerability requires the victim to be authenticated to MISP and to actively visit the attacker-supplied URL. The affected component is the AnalystData controller and the Overmind theme's AnalystData thread element. Version affected: <2.5.47

Source: CVE List, as of 29 Oct 2026. About the data.

Timeline