FKIE_CVE-2026-97993

Vulnerability from fkie_nvd - Published: 2026-09-25 11:17 - Updated: 2026-09-25 11:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: vhost-vdpa: don't install the eventfd_ctx_fdget() error in config_ctx vhost_vdpa_set_config_call() swaps the eventfd_ctx_fdget() return value into v->config_ctx before checking it, so on failure the field briefly holds an ERR_PTR: ctx = fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(fd); swap(ctx, v->config_ctx); if (!IS_ERR_OR_NULL(ctx)) eventfd_ctx_put(ctx); if (IS_ERR(v->config_ctx)) { long ret = PTR_ERR(v->config_ctx); v->config_ctx = NULL; return ret; } Commit 0bde59c1723a ("vhost-vdpa: set v->config_ctx to NULL if eventfd_ctx_fdget() fails") added that clearing, and spelled out the invariant the rest of the file relies on: "we consider 'v->config_ctx' valid if it is not NULL". The window between the swap and the clearing still breaks it. vhost_vdpa_config_cb() only tests for NULL, so a config interrupt delivered inside the window hands the ERR_PTR to eventfd_signal(). Check the fd before installing it instead. That closes the window and matches how vhost_vring_ioctl() handles the same failure for the vq call fd. It also stops a rejected fd from tearing down a config interrupt that was working: until now the swap replaced the live context and put it, so after an EBADF the device silently stopped delivering config interrupts until userspace installed a new fd.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/388c678639a0cebfd936b3e56c64ac6a371efec2
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/65faf9eaa00e408e1406fbcf675c8c8d0e27ff2a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6b20b40f020bde236f6b8a08ff88d8653261ec2b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e74a9fa50749b9940b4fb13199652325e08d3c4a
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/vhost/vdpa.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "388c678639a0cebfd936b3e56c64ac6a371efec2",
              "status": "affected",
              "version": "776f395004d829bbbf18c159ed9beb517a208c71",
              "versionType": "git"
            },
            {
              "lessThan": "65faf9eaa00e408e1406fbcf675c8c8d0e27ff2a",
              "status": "affected",
              "version": "776f395004d829bbbf18c159ed9beb517a208c71",
              "versionType": "git"
            },
            {
              "lessThan": "6b20b40f020bde236f6b8a08ff88d8653261ec2b",
              "status": "affected",
              "version": "776f395004d829bbbf18c159ed9beb517a208c71",
              "versionType": "git"
            },
            {
              "lessThan": "e74a9fa50749b9940b4fb13199652325e08d3c4a",
              "status": "affected",
              "version": "776f395004d829bbbf18c159ed9beb517a208c71",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/vhost/vdpa.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.8"
            },
            {
              "lessThan": "5.8",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvhost-vdpa: don\u0027t 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 \u0027v-\u003econfig_ctx\u0027\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."
    }
  ],
  "id": "CVE-2026-97993",
  "lastModified": "2026-09-25T11:17:27.500",
  "metrics": {},
  "published": "2026-09-25T11:17:27.500",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/388c678639a0cebfd936b3e56c64ac6a371efec2"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/65faf9eaa00e408e1406fbcf675c8c8d0e27ff2a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6b20b40f020bde236f6b8a08ff88d8653261ec2b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e74a9fa50749b9940b4fb13199652325e08d3c4a"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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