CVE-2026-97993
Received Received - Intake

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Vulnerability report for CVE-2026-97993, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-09-25

Last updated on: 2026-10-03

Assigner: kernel.org

Description

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.

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Meta Information

Published
2026-09-25
Last Modified
2026-10-03
Generated
2026-10-15
AI Q&A
2026-09-25
EPSS Evaluated
2026-10-14
NVD
EUVD

Affected Vendors & Products

Showing 9 associated CPEs
Vendor Product Version / Range
Linux Linux 776f395004d829bbbf18c159ed9beb517a208c71
Linux Linux 776f395004d829bbbf18c159ed9beb517a208c71
Linux Linux 776f395004d829bbbf18c159ed9beb517a208c71
Linux Linux 776f395004d829bbbf18c159ed9beb517a208c71
Linux Linux 776f395004d829bbbf18c159ed9beb517a208c71
Linux Linux 776f395004d829bbbf18c159ed9beb517a208c71
Linux Linux 776f395004d829bbbf18c159ed9beb517a208c71
Linux Linux 776f395004d829bbbf18c159ed9beb517a208c71
Linux Linux 5.8

Helpful Resources

Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves improper handling of an error pointer in the vhost-vdpa subsystem. The issue occurs when vhost_vdpa_set_config_call() swaps a potentially invalid eventfd context into a field before checking for errors, creating a brief window where an error pointer (ERR_PTR) is stored. This can lead to a config interrupt being delivered with an invalid pointer, causing a crash when eventfd_signal() is called.

Detection Guidance

This vulnerability is specific to the Linux kernel's vhost-vdpa subsystem and does not have direct network detection methods. Detection involves checking kernel logs for errors related to vhost-vdpa or config_ctx handling. Commands like dmesg | grep vhost or journalctl -k | grep vhost may help identify issues.

Impact Analysis

If exploited, this vulnerability could cause a denial-of-service condition by crashing the system when a config interrupt is processed with an invalid eventfd context. It may also lead to unexpected behavior where a rejected file descriptor silently disables config interrupts until a new one is installed.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards as it is a low-level kernel issue related to eventfd handling in the vhost-vdpa subsystem. No data exposure or privacy implications are described in the provided context.

Mitigation Strategies

Apply the kernel patch that resolves this issue. Update your Linux kernel to a version containing the fix (commit 0bde59c1723a or later). If immediate patching is not possible, monitor for vhost-vdpa related errors and avoid using vhost-vdpa with untrusted file descriptors.

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