{"id":"CVE-2026-97993","title":"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…","summary":"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…","severity":"medium","vendor":"Linux","product":"Linux","affected":["Linux >= 776f395004d829bbbf18c159ed9beb517a208c71 < e260dc9fbfdae0978e7a8698f977fbb463a657be","Linux >= 776f395004d829bbbf18c159ed9beb517a208c71 < 66e73fa18910b39fea0941dea5fe091122240855","Linux >= 776f395004d829bbbf18c159ed9beb517a208c71 < 4fde085eb839fbb39c25cbba5d2a091ded394877","Linux >= 776f395004d829bbbf18c159ed9beb517a208c71 < 59fc7c1c6b4d325194ca45352180340092d95098","Linux >= 776f395004d829bbbf18c159ed9beb517a208c71 < 388c678639a0cebfd936b3e56c64ac6a371efec2","Linux >= 776f395004d829bbbf18c159ed9beb517a208c71 < 65faf9eaa00e408e1406fbcf675c8c8d0e27ff2a","Linux >= 776f395004d829bbbf18c159ed9beb517a208c71 < 6b20b40f020bde236f6b8a08ff88d8653261ec2b","Linux >= 776f395004d829bbbf18c159ed9beb517a208c71 < e74a9fa50749b9940b4fb13199652325e08d3c4a","Linux 5.8"],"published":"2026-09-25","updated":"2026-10-03","sourceUpdated":"2026-10-03T11:18:22.997","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-97993","references":[{"url":"https://git.kernel.org/stable/c/388c678639a0cebfd936b3e56c64ac6a371efec2","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/4fde085eb839fbb39c25cbba5d2a091ded394877","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/59fc7c1c6b4d325194ca45352180340092d95098","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/65faf9eaa00e408e1406fbcf675c8c8d0e27ff2a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/66e73fa18910b39fea0941dea5fe091122240855","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/6b20b40f020bde236f6b8a08ff88d8653261ec2b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e260dc9fbfdae0978e7a8698f977fbb463a657be","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e74a9fa50749b9940b4fb13199652325e08d3c4a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97993.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-97993"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2541314"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-97993"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-97993"},{"url":"https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-97993.mbox"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"epss":0.00216,"epssPercentile":0.11986,"ingestedAt":"2026-09-25T11:06:38.864Z","cvss":5.5,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cvssSource":"vendor","cwe":["CWE-366"],"slug":"CVE-2026-97993","body":"## Overview\n\nIn 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Low · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-10-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97993.json)","depth":"sunlit","depthScore":30,"depthScoreParts":{"impact":30.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":224175,"id":"CVE-2026-97993","ts":1792324984988,"field":"cvss","old":null,"new":"5.5"},{"seq":224174,"id":"CVE-2026-97993","ts":1792324984988,"field":"severity","old":"none","new":"medium"}]}