-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-26:20.fusefs Security Advisory The FreeBSD Project Topic: Heap overflow in FUSE_LISTXATTR Category: core Module: fusefs Announced: 2026-05-20 Credits: Joshua Rogers of AISLE Research Team Affects: All supported versions of FreeBSD. Corrected: 2026-05-20 19:36:38 UTC (stable/15, 15.0-STABLE) 2026-05-20 19:39:32 UTC (releng/15.0, 15.0-RELEASE-p9) 2026-05-20 19:37:58 UTC (stable/14, 14.4-STABLE) 2026-05-20 19:39:58 UTC (releng/14.4, 14.4-RELEASE-p5) 2026-05-20 19:40:36 UTC (releng/14.3, 14.3-RELEASE-p14) CVE Name: CVE-2026-45252 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit <URL:https://security.FreeBSD.org/>. I. Background The fusefs file system delegates file system operations to a userspace daemon. This daemon ordinarily requires root privileges to operate. When the "vfs.usermount" sysctl is set to 1 (not the default), unprivileged users are permitted to run such daemons and mount fusefs file systems. II. Problem Description When a fusefs file system implements extended attributes, the kernel may send a FUSE_LISTXATTR message to the userspace daemon to retrieve the list of extended attributes for a given file. The FUSE protocol requires the daemon to return a packed list of NUL-terminated strings. The fusefs kernel module calls strlen() on this daemon-supplied buffer without first verifying that the entire list is NUL-terminated. III. Impact If a malicious daemon sends a non-NUL-terminated list, the fusefs kernel module may read beyond the end of one heap-allocated buffer and potentially write beyond the end of a second buffer. A malicious daemon could disclose up to 253 bytes of kernel heap memory, or it could inject up to 250 attacker-controlled bytes into unallocated kernel heap space. IV. Workaround No workaround is available, but systems that do not load the fusefs kernel module or set vfs.usermount=1 are unaffected. V. Solution Upgrade your vulnerable system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date, and reboot the system. Perform one of the following: 1) To update your vulnerable system installed from base system packages: Systems running a 15.0-RELEASE version of FreeBSD on the amd64 or arm64 platforms, which were installed using base system packages, can be updated via the pkg(8) utility: # pkg upgrade -r FreeBSD-base # shutdown -r +10min "Rebooting for a security update" 2) To update your vulnerable system installed from binary distribution sets: Systems running a RELEASE version of FreeBSD on the amd64 or arm64 platforms which were not installed using base system packages can be updated via the freebsd-update(8) utility: # freebsd-update fetch # freebsd-update install # shutdown -r +10min "Rebooting for a security update" 3) To update your vulnerable system via a source code patch: The following patches have been verified to apply to the applicable FreeBSD release branches. a) Download the relevant patch from the location below, and verify the detached PGP signature using your PGP utility. [FreeBSD 15.0] # fetch https://security.FreeBSD.org/patches/SA-26:20/fusefs-15.patch # fetch https://security.FreeBSD.org/patches/SA-26:20/fusefs-15.patch.asc # gpg --verify fusefs-15.patch.asc [FreeBSD 14.4] # fetch https://security.FreeBSD.org/patches/SA-26:20/fusefs-14.4.patch # fetch https://security.FreeBSD.org/patches/SA-26:20/fusefs-14.4.patch.asc # gpg --verify fusefs-14.4.patch.asc [FreeBSD 14.3] # fetch https://security.FreeBSD.org/patches/SA-26:20/fusefs-14.3.patch # fetch https://security.FreeBSD.org/patches/SA-26:20/fusefs-14.3.patch.asc # gpg --verify fusefs-14.3.patch.asc b) Apply the patch. Execute the following commands as root: # cd /usr/src # patch < /path/to/patch c) Recompile your kernel as described in <URL:https://www.FreeBSD.org/handbook/kernelconfig.html> and reboot the system. VI. Correction details This issue is corrected as of the corresponding Git commit hash in the following stable and release branches: Branch/path Hash Revision - ------------------------------------------------------------------------- stable/15/ df3f3fa82775 stable/15-n283642 releng/15.0/ 0dd8b983db3c releng/15.0-n281042 stable/14/ 25148c51c8c6 stable/14-n274165 releng/14.4/ 6a299460f159 releng/14.4-n273705 releng/14.3/ 53f3bf4ee1ce releng/14.3-n271505 - ------------------------------------------------------------------------- Run the following command to see which files were modified by a particular commit: # git show --stat <commit hash> Or visit the following URL, replacing NNNNNN with the hash: <URL:https://cgit.freebsd.org/src/commit/?id=NNNNNN> To determine the commit count in a working tree (for comparison against nNNNNNN in the table above), run: # git rev-list --count --first-parent HEAD VII. References <URL:https://www.cve.org/CVERecord?id=CVE-2026-45252> The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-26:20.fusefs.asc> -----BEGIN PGP SIGNATURE----- iQJPBAEBCgA5FiEEthUnfoEIffdcgYM7bljekB8AGu8FAmoOKHIbFIAAAAAABAAO bWFudTIsMi41KzEuMTIsMCwzAAoJEG5Y3pAfABrvobkP/R3O3bwsnJkhG1NQ6pKh UFcwpZ8TSAqtccHZRQz2zoKTqu/EeClT7Bdgw/Qa8gbZ7IfZgS8AJaR7e4fgpE96 AhHU6cbyZrpwvWUatIKgX57032+M1ioMiz9g0KbGg4W4WKe/QHj4yt45F7qRfLNb BD7Qp7E0XtV+UrNXkhOQQmHyVTpB85tK/e5Yc+vcSgAQ3LWrzwO4zED4f78e3faw oiLm1oE/Vx0jfrRKsnCECdJS532xlfH6iJ2/2ZXfUthGQmZQe34wOMwYS0EcaGZV TQoLwsg5qLj4hJOGMCZk4X4TjrkoQquWdsAQetB8tqXIyw7QEgbMIIbhS3mQZ5CW aEq3wbYMowxCMb/6Dd/R56wDqyGI2Z6GHmUT58M0OSIIISfsD+UHOCW2lrQQ5zrI o1O/IFAvqsmCN6JQzFgC3KC8BLLZWzxf5Bun6yOls/YA31zOXAen0isnbOvVnGot 42Dy65fENCUQMt+p3eDDLQzxDhlqGAGbiqysBmxwTA5Wqc4furv7O0wmBPwOOGeH NqlKYsqO9u4kEW2lTCPs7R5+wsc+EACc07kikDQgp1m59JlkMfmXU4Kbcgw9r4GR 9OWtidfTCDGmt9mXzJVKaBurgJ1iqsBfzzLamWo0iDpUMgUP7VA9jVjVbUmtjH1V qAWdXCXwrbOr+eA50IIPxkal =HzW3 -----END PGP SIGNATURE-----
No comments:
Post a Comment