CVE-2026-97993
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.
No affected software listed.
- https://git.kernel.org/stable/c/388c678639a0cebfd936b3e56c64ac6a371efec2
- https://git.kernel.org/stable/c/4fde085eb839fbb39c25cbba5d2a091ded394877
- https://git.kernel.org/stable/c/59fc7c1c6b4d325194ca45352180340092d95098
- https://git.kernel.org/stable/c/65faf9eaa00e408e1406fbcf675c8c8d0e27ff2a
- https://git.kernel.org/stable/c/66e73fa18910b39fea0941dea5fe091122240855
- https://git.kernel.org/stable/c/6b20b40f020bde236f6b8a08ff88d8653261ec2b
- https://git.kernel.org/stable/c/e260dc9fbfdae0978e7a8698f977fbb463a657be
- https://git.kernel.org/stable/c/e74a9fa50749b9940b4fb13199652325e08d3c4a
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A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.
CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.
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