{"id":"CVE-2026-97993","published":"2026-09-25T11:17:27.500","lastModified":"2026-09-25T11:17:27.500","description":"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->config_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->config_ctx);\n\n\tif (!IS_ERR_OR_NULL(ctx))\n\t\teventfd_ctx_put(ctx);\n\n\tif (IS_ERR(v->config_ctx)) {\n\t\tlong ret = PTR_ERR(v->config_ctx);\n\n\t\tv->config_ctx = NULL;\n\t\treturn ret;\n\t}\n\nCommit 0bde59c1723a (\"vhost-vdpa: set v->config_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->config_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.","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/388c678639a0cebfd936b3e56c64ac6a371efec2","tags":[]},{"url":"https://git.kernel.org/stable/c/65faf9eaa00e408e1406fbcf675c8c8d0e27ff2a","tags":[]},{"url":"https://git.kernel.org/stable/c/6b20b40f020bde236f6b8a08ff88d8653261ec2b","tags":[]},{"url":"https://git.kernel.org/stable/c/e74a9fa50749b9940b4fb13199652325e08d3c4a","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}