-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= pfSense-SA-26_12.webgui Security Advisory pfSense Topic: Stored XSS in DHCPv4 Pool Descriptions Category: pfSense Base System Module: webgui Announced: 2026-08-13 Credits: @lujiefsi Affects: pfSense Plus software versions < 26.07 pfSense CE software versions <= 2.8.1 Corrected: 2026-07-10 15:42:30 UTC (pfSense Plus master, 26.10) 2026-07-10 16:06:50 UTC (pfSense Plus plus-RELENG_26_07, 26.07) 2026-07-10 15:42:30 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 services_dhcp.php when adding or editing address pools. When adding or editing a DHCPv4 pool, the services_dhcp.php page prints the descr field of existing pools without encoding. 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 DHCP address pools saves a specially-crafted payload in a pool description, it could trigger an XSS when adding or editing a DHCPv4 pool on services_dhcp.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 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 3850c6a1ca136da40f3ddd6ba791013055e1ab6d plus/plus-RELENG_26_07 2353bb80d3c8f5071644cf8c5c7f2aa71b57b497 pfSense/master 3850c6a1ca136da40f3ddd6ba791013055e1ab6d - - ------------------------------------------------------------------------- VII. References The latest revision of this advisory is available at -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEE40XvjEU56XSUPIMdE7mH/ZIU+NoFAmp+HqQACgkQE7mH/ZIU +NregxAA2ORtiQZXly2JdT5sq2yuLvUYA2amsHH6q/mMmwWmh+0hkJ75ONj/6wTz ULKbT3ZMSRzEYD36lmDYn2KMa3WS68Ok6ywb4zwp/wU7h1Gis8sEcpRvWGhDnaWZ O/FzCKp0gXxSN4dUq9W/tq8JjhOUEcbcCN7/XRaY282i66HgN4zQe9hMed2/pixs JSx1gsrOa6e/I/dm1LGNvRbHGmJeFiEblTYWYiavi2K7PYeprB17d5tQlQXG7zec CTLAeadx6A5pJxPqZm+p/6S2cTSD2c+X6jxo4B+ox+AkBFi9M1HpzpICSousKmk/ yOtSVp13Akp/Fgk/vDwBYd963hT6xt1FuF+gc5YP8hlsUbMg3ZCAWtCislwgHPbh auG124njfGwWJf82+rSjTsZm+eEui5TSuPItGLWNK4c0E2FexCz9i+Tvz2GM8B23 iT2PMgLX+GIk70ekmo7eNdJXzK9FfCbyP30UN81s4EGs//PZ4nL+97wcPu2/M0pW nGg/VxsHLFa0zme/z2iRpY+nMD+LAcoPuvINtFZfc9lgALddpN2diQ2qSk5tz7bl YQ/5LYxSJgBwA+ZGAHdX94Xr1HoPqxcDXSD9k3wUwUuKfHlCRFe2mlZePMtcv/gw TzQ2Ngw0TIDTIIWJLmUwNl72GPCGwvqaB1qcSHuHdKxL9uzIM0Y= =3ks7 -----END PGP SIGNATURE-----