CVE-2026-64293
iommufd: Use sizeof(*hdr) instead of sizeof(hdr) in veventq read
Description
In the Linux kernel, the following vulnerability has been resolved: iommufd: Use sizeof(*hdr) instead of sizeof(hdr) in veventq read The bound-check in iommufd_veventq_fops_read() for the normal vEVENT path uses sizeof(hdr) where the surrounding code uses sizeof(*hdr): if (!vevent_for_lost_events_header(cur) && sizeof(hdr) + cur->data_len > count - done) { hdr is declared as struct iommufd_vevent_header *, so sizeof(hdr) evaluates to the size of the pointer. Surrounding code uses sizeof(*hdr) consistently: if (done >= count || sizeof(*hdr) > count - done) { ... if (copy_to_user(buf + done, hdr, sizeof(*hdr))) { ... done += sizeof(*hdr); struct iommufd_vevent_header is currently 8 bytes (two __u32 fields, flags and sequence), so on 64-bit (sizeof(void *) == 8) the two expressions happen to be equal and the check works as intended. On 32-bit (sizeof(void *) == 4) the check under-counts the header by 4 bytes: a vEVENT whose data_len causes 8 + cur->data_len to exceed count - done while 4 + cur->data_len does not will pass the check, then the loop will copy_to_user 8 bytes of header followed by data_len bytes of payload, writing past the user-supplied buffer. It is also a latent bug for any future expansion of struct iommufd_vevent_header beyond sizeof(void *) on 64-bit; the check should not depend on the type happening to match the host pointer width. Use sizeof(*hdr) to match the rest of the function and the actual amount that will be copied.
INFO
Published Date :
July 25, 2026, 10:17 a.m.
Last Modified :
Aug. 17, 2026, 5:17 a.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
- Update the Linux kernel to the patched version.
- Verify the patch is applied successfully.
- Test the iommufd functionality.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-64293.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-64293 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-64293
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-64293 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-64293 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Aug. 17, 2026
Action Type Old Value New Value Changed Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'e36ba5ab808ef6237c3148d469c8238674230e2b', 'lessThan': '04a177f91160ee18da98f5689482cf0f589ec869', 'versionType': 'git'}, {'status': 'affected', 'version': 'e36ba5ab808ef6237c3148d469c8238674230e2b', 'lessThan': '0cdbb97a4dbd69abdd2ab998b4fbc7803d4b0b72', 'versionType': 'git'}, {'status': 'affected', 'version': 'e36ba5ab808ef6237c3148d469c8238674230e2b', 'lessThan': 'be93d186ae88a92e7aa77e122d4e661fa57b1e39', 'versionType': 'git'}], 'programFiles': ['drivers/iommu/iommufd/eventq.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.15'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.15', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.18.39', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.4', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['drivers/iommu/iommufd/eventq.c'], 'defaultStatus': 'affected'}] [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'e36ba5ab808ef6237c3148d469c8238674230e2b', 'lessThan': '04a177f91160ee18da98f5689482cf0f589ec869', 'versionType': 'git'}, {'status': 'affected', 'version': 'e36ba5ab808ef6237c3148d469c8238674230e2b', 'lessThan': '0cdbb97a4dbd69abdd2ab998b4fbc7803d4b0b72', 'versionType': 'git'}, {'status': 'affected', 'version': 'e36ba5ab808ef6237c3148d469c8238674230e2b', 'lessThan': 'be93d186ae88a92e7aa77e122d4e661fa57b1e39', 'versionType': 'git'}], 'programFiles': ['drivers/iommu/iommufd/eventq.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.15'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.15', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.18.39', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.4', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['drivers/iommu/iommufd/eventq.c'], 'defaultStatus': 'affected'}] -
Initial Analysis by [email protected]
Aug. 12, 2026
Action Type Old Value New Value Added CWE NVD-CWE-noinfo Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 7.1.4 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.15 up to (excluding) 6.18.39 Added Reference Type kernel.org: https://git.kernel.org/stable/c/04a177f91160ee18da98f5689482cf0f589ec869 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/0cdbb97a4dbd69abdd2ab998b4fbc7803d4b0b72 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/be93d186ae88a92e7aa77e122d4e661fa57b1e39 Types: Patch -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jul. 27, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jul. 25, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'e36ba5ab808ef6237c3148d469c8238674230e2b', 'lessThan': '04a177f91160ee18da98f5689482cf0f589ec869', 'versionType': 'git'}, {'status': 'affected', 'version': 'e36ba5ab808ef6237c3148d469c8238674230e2b', 'lessThan': '0cdbb97a4dbd69abdd2ab998b4fbc7803d4b0b72', 'versionType': 'git'}, {'status': 'affected', 'version': 'e36ba5ab808ef6237c3148d469c8238674230e2b', 'lessThan': 'be93d186ae88a92e7aa77e122d4e661fa57b1e39', 'versionType': 'git'}], 'programFiles': ['drivers/iommu/iommufd/eventq.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.15'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.15', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.18.39', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.1.4', 'versionType': 'semver', 'lessThanOrEqual': '7.1.*'}, {'status': 'unaffected', 'version': '7.2-rc1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['drivers/iommu/iommufd/eventq.c'], 'defaultStatus': 'affected'}] Added Description In the Linux kernel, the following vulnerability has been resolved: iommufd: Use sizeof(*hdr) instead of sizeof(hdr) in veventq read The bound-check in iommufd_veventq_fops_read() for the normal vEVENT path uses sizeof(hdr) where the surrounding code uses sizeof(*hdr): if (!vevent_for_lost_events_header(cur) && sizeof(hdr) + cur->data_len > count - done) { hdr is declared as struct iommufd_vevent_header *, so sizeof(hdr) evaluates to the size of the pointer. Surrounding code uses sizeof(*hdr) consistently: if (done >= count || sizeof(*hdr) > count - done) { ... if (copy_to_user(buf + done, hdr, sizeof(*hdr))) { ... done += sizeof(*hdr); struct iommufd_vevent_header is currently 8 bytes (two __u32 fields, flags and sequence), so on 64-bit (sizeof(void *) == 8) the two expressions happen to be equal and the check works as intended. On 32-bit (sizeof(void *) == 4) the check under-counts the header by 4 bytes: a vEVENT whose data_len causes 8 + cur->data_len to exceed count - done while 4 + cur->data_len does not will pass the check, then the loop will copy_to_user 8 bytes of header followed by data_len bytes of payload, writing past the user-supplied buffer. It is also a latent bug for any future expansion of struct iommufd_vevent_header beyond sizeof(void *) on 64-bit; the check should not depend on the type happening to match the host pointer width. Use sizeof(*hdr) to match the rest of the function and the actual amount that will be copied. Added Reference https://git.kernel.org/stable/c/04a177f91160ee18da98f5689482cf0f589ec869 Added Reference https://git.kernel.org/stable/c/0cdbb97a4dbd69abdd2ab998b4fbc7803d4b0b72 Added Reference https://git.kernel.org/stable/c/be93d186ae88a92e7aa77e122d4e661fa57b1e39