-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= pfSense-SA-26_11.webgui Security Advisory pfSense Topic: Stored XSS in Firewall Rule list schedules Category: pfSense Base System Module: webgui Announced: 2026-08-13 Credits: Alex Williams from Pellera Technologies CVE ID: CVE-2026-56128 Affects: pfSense Plus software versions < 26.07 pfSense CE software versions <= 2.8.1 Corrected: 2026-07-01 19:35:52 UTC (pfSense Plus master, 26.10) 2026-07-01 19:37:28 UTC (pfSense Plus plus-RELENG_26_07, 26.07) 2026-07-01 19:35:52 UTC (pfSense CE master, 2.9.0) 0. Revision History v1.0 2026-08-13 Initial SA draft I. Background pfSense® software is a free network firewall distribution based on the FreeBSD operating system. The pfSense software distribution includes third- party free software packages for additional functionality, and provides most of the functionality of common commercial firewalls. pfSense® Plus is the productized version of pfSense software from Netgate®, previously referred to as pfSense Factory Edition (FE). It is available to Netgate appliance and CSP customers. The majority of users of pfSense software have never installed or used a stock FreeBSD system. Unlike similar GNU/Linux-based firewall distributions, there is no need for any UNIX knowledge. The command line is never used, and there is no need to ever manually edit any rule sets. Instead, pfSense software includes a web interface for the configuration of all included components. Users familiar with commercial firewalls will quickly understand the web interface, while those unfamiliar with commercial-grade firewalls may encounter a short learning curve. II. Problem Description A potential stored Cross-Site Scripting (XSS) vulnerability was identified in the firewall rule list on firewall_rules.php when a rule contains a schedule. The page prints firewall rule schedule descriptions without sufficient encoding. The page escapes single quotes in the description, but an XSS payload using double quotes is not escaped. This problem is present on pfSense Plus version 26.03.1, pfSense CE version 2.8.1, and earlier versions of both. III. Impact If an attacker with the ability to create or edit firewall rules and schedules saves a specially-crafted payload in a firewall schedule description and that schedule is in use on a firewall rule, it could trigger an XSS when viewing the firewall rule list on firewall_rules.php. Arbitrary JavaScript could be executed in the user's browser. The user's session cookie or other information from the session may be compromised. IV. Workaround To help mitigate the problem on older releases, use one or more of the following: * Limit access to functions which allow creating arbitrary directories on the filesystem. * Limit access to the affected pages to trusted administrators only. * Do not log into the firewall with the same browser used for non- administrative web browsing. V. Solution Users can upgrade to pfSense Plus software version 26.07 or later, or pfSense CE software versions after 2.8.1 when available. This upgrade may be performed in the web interface or from the console. See https://docs.netgate.com/pfsense/en/latest/install/upgrade-guide.html Users on pfSense Plus version 26.03.1 and pfSense CE version 2.8.1 may apply the fix from the recommended patches list in the System Patches package after installing or updating the System Patches package. Users may also manually apply the relevant changes using the System Patches package on earlier versions, or by manually making similar changes to the affected files if the patches do not apply directly. See https://docs.netgate.com/pfsense/en/latest/development/system-patches.html VI. Correction details The following list contains the correction revision commit ID for each affected item. Branch/path Revision - - ------------------------------------------------------------------------- plus/plus-master b20191f85405a218d996171c8a0199d35f101c6a plus/plus-RELENG_26_07 6c7e24eb5422b1216021d0a78fce12b20d676016 pfSense/master b20191f85405a218d996171c8a0199d35f101c6a - - ------------------------------------------------------------------------- VII. References The latest revision of this advisory is available at -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEE40XvjEU56XSUPIMdE7mH/ZIU+NoFAmp+HqAACgkQE7mH/ZIU +Np8eRAAkIE+o/SKWBmZJuCzoM9ZrHbDMaxeBNE+aWtcyvrPo0CvVbzZb1dRdqa8 5pcZhirduQOkKjuH0IcH/OFAOznnzU9OwMlLxEn9JJpYi1ZNVkNkPCTUDViIqDcR iTOiWFJ80jNxsIovW2opVDtv/Kbvb0A+6mo54Ky/dIm4Kxn9s5l1A42k3pntO5dr nCskWF+DEv2lRpoEajyMbwWQPzJnxW2TLdETRFwLPMlKSlf3orgOz6jL1DRSvWlt oXvKY9PYsRfNx+BQzDOog0JZEf4FwEo+W5a9uFKm83NiegN1vWX04L37OQRaFIHS eBghd0/iokVgp9LYYI35/2OyWd6EjTJwvJY5xj85C56oENv0MqYSwf/YeXJL5zKm zxdZ3zQqpgk+G9HCmO/89WjM4+7pZfS2JsPQsLMByZ5zB9uAuDC+xG4oviPTosba hMvKQmYBhQeRcUTto4oKHCrAxx3CmYg3Vps1tms7yxW66JazGFCquU1f3b7cTt+K +v8qOjopEhJMUSVQV7ysijXSRyA4cHVv/IF7kwbBaJb4K9rzt9u32jHIzyOcHg0K F+cEoXWfV4cF8qy2TDGSnkh8MESVXW4bHWXodVe/rKpQg0+ohwKbKe7vW/0AzI6x 8123TwDFS0qgw2rZgd8M0X7mkZaPKyntI+euDfApOWZ3a7za/Ks= =qDiB -----END PGP SIGNATURE-----