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CVE-2026-97993

vhost-vdpa: don't install the eventfd_ctx_fdget() error in config_ctx

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, and 2 more
None on Exploit-DB, Metasploit or GitHub

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.

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • Linux Linux

    From 776f395004d829bbbf18c159ed9beb517a208c71 · fixed in e260dc9fbfdae0978e7a8698f977fbb463a657be; From 776f395004d829bbbf18c159ed9beb517a208c71 · fixed in 66e73fa18910b39fea0941dea5fe091122240855; From 776f395004d829bbbf18c159ed9beb517a208c71 · fixed in 4fde085eb839fbb39c25cbba5d2a091ded394877; From 776f395004d829bbbf18c159ed9beb517a208c71 · fixed in 59fc7c1c6b4d325194ca45352180340092d95098; From 776f395004d829bbbf18c159ed9beb517a208c71 · fixed in 388c678639a0cebfd936b3e56c64ac6a371efec2; From 776f395004d829bbbf18c159ed9beb517a208c71 · fixed in 65faf9eaa00e408e1406fbcf675c8c8d0e27ff2a; From 776f395004d829bbbf18c159ed9beb517a208c71 · fixed in 6b20b40f020bde236f6b8a08ff88d8653261ec2b; From 776f395004d829bbbf18c159ed9beb517a208c71 · fixed in e74a9fa50749b9940b4fb13199652325e08d3c4a

  • Linux Linux

    5.8

  • KernelLinux

    From 5.8.0 · fixed in 5.10.271; From 5.11.0 · fixed in 5.15.222; From 5.16.0 · fixed in 6.1.189; From 6.2.0 · fixed in 6.6.158; From 6.7.0 · fixed in 6.12.111; From 6.13.0 · fixed in 6.18.53; From 6.19.0 · fixed in 7.2.7

References 8

git.kernel.org