Vulnerability · Published Aug 3, 2026 · Assigned by VulnCheck

CVE-2026-49131OPNsense < 26.1.9 Stored XSS via Firewall Rule Description Field

Medium 5.4

In plain English

A medium-severity cross-site scripting in OPNsense from Deciso B.V.. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 22% of all known vulnerabilities).

Severity (CVSS 3.1)5.4Medium

Exploit odds (30 days)0.3%top 78.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

OPNsense before 26.1.9 contains a stored cross-site scripting vulnerability that allows authenticated attackers with firewall rule management privileges to inject arbitrary HTML or JavaScript by embedding payloads in the firewall rule description field via the filter API endpoint. The unsanitized description value is persisted and later rendered through the default cell formatter in opnsense_bootgrid.js, which assigns raw cell content to innerHTML, causing injected scripts to execute in the browser of any authenticated user who views the Firewall Rules page, enabling session hijacking or credential theft.

Affected products (as reported)

Vendor	Product	Versions
Deciso B.V.	OPNsense	0 – before 26.1.9

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

References

Release Notes release-notes
Patch Commit patch
https://www.vulncheck.com/advisories/opnsense-stored-xss-via-firewall-rule-description-field third-party-advisory