{"id":"CVE-2026-97993","summary":"vhost-vdpa: don't install the eventfd_ctx_fdget() error in config_ctx","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nvhost-vdpa: don't install the eventfd_ctx_fdget() error in config_ctx\n\nvhost_vdpa_set_config_call() swaps the eventfd_ctx_fdget() return value\ninto v-\u003econfig_ctx before checking it, so on failure the field briefly\nholds an ERR_PTR:\n\n\tctx = fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(fd);\n\tswap(ctx, v-\u003econfig_ctx);\n\n\tif (!IS_ERR_OR_NULL(ctx))\n\t\teventfd_ctx_put(ctx);\n\n\tif (IS_ERR(v-\u003econfig_ctx)) {\n\t\tlong ret = PTR_ERR(v-\u003econfig_ctx);\n\n\t\tv-\u003econfig_ctx = NULL;\n\t\treturn ret;\n\t}\n\nCommit 0bde59c1723a (\"vhost-vdpa: set v-\u003econfig_ctx to NULL if\neventfd_ctx_fdget() fails\") added that clearing, and spelled out the\ninvariant the rest of the file relies on: \"we consider 'v-\u003econfig_ctx'\nvalid if it is not NULL\".  The window between the swap and the clearing\nstill breaks it.  vhost_vdpa_config_cb() only tests for NULL, so a config\ninterrupt delivered inside the window hands the ERR_PTR to\neventfd_signal().\n\nCheck the fd before installing it instead.  That closes the window and\nmatches how vhost_vring_ioctl() handles the same failure for the vq call\nfd.\n\nIt also stops a rejected fd from tearing down a config interrupt that was\nworking: until now the swap replaced the live context and put it, so\nafter an EBADF the device silently stopped delivering config interrupts\nuntil userspace installed a new fd.","modified":"2026-09-26T03:48:31.035911123Z","published":"2026-09-25T10:23:25.110Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97993.json"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/388c678639a0cebfd936b3e56c64ac6a371efec2"},{"type":"WEB","url":"https://git.kernel.org/stable/c/65faf9eaa00e408e1406fbcf675c8c8d0e27ff2a"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6b20b40f020bde236f6b8a08ff88d8653261ec2b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e74a9fa50749b9940b4fb13199652325e08d3c4a"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97993.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-97993"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"776f395004d829bbbf18c159ed9beb517a208c71"},{"fixed":"388c678639a0cebfd936b3e56c64ac6a371efec2"},{"fixed":"65faf9eaa00e408e1406fbcf675c8c8d0e27ff2a"},{"fixed":"6b20b40f020bde236f6b8a08ff88d8653261ec2b"},{"fixed":"e74a9fa50749b9940b4fb13199652325e08d3c4a"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-97993.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.8.0"},{"fixed":"6.12.111"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.53"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.7"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-97993.json"}}],"schema_version":"1.9.0"}