Linux Kernel up to 6.18.38/7.1.3 iommufd iommufd_veventq_fops_read data_len buffer overflow

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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9.5$5k-$25k3.10-

Summaryinfo

A vulnerability categorized as very critical has been discovered in Linux Kernel up to 6.18.38/7.1.3. This issue affects the function iommufd_veventq_fops_read of the component iommufd. Such manipulation of the argument data_len leads to buffer overflow. This vulnerability is referenced as CVE-2026-64293. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.18.38/7.1.3 and classified as very critical. Affected by this issue is the function iommufd_veventq_fops_read of the component iommufd. The manipulation of the argument data_len with an unknown input leads to a buffer overflow vulnerability. Using CWE to declare the problem leads to CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at git.kernel.org. This vulnerability is handled as CVE-2026-64293 since 07/19/2026. The exploitation is known to be easy. The attack may be launched remotely. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 07/25/2026).

Upgrading to version 6.18.39, 7.1.4 or 7.2-rc1 eliminates this vulnerability. Applying the patch 04a177f91160ee18da98f5689482cf0f589ec869/0cdbb97a4dbd69abdd2ab998b4fbc7803d4b0b72/be93d186ae88a92e7aa77e122d4e661fa57b1e39 is able to eliminate this problem.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

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Version

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.9
VulDB Meta Temp Score: 9.5

VulDB Base Score: 9.9
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Buffer overflow
CWE: CWE-120 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.18.39/7.1.4/7.2-rc1
Patch: 04a177f91160ee18da98f5689482cf0f589ec869/0cdbb97a4dbd69abdd2ab998b4fbc7803d4b0b72/be93d186ae88a92e7aa77e122d4e661fa57b1e39

Timelineinfo

07/19/2026 CVE reserved
07/25/2026 +6 days Advisory disclosed
07/25/2026 +0 days VulDB entry created
07/25/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-64293 (🔒)
GCVE (CVE): GCVE-0-2026-64293
GCVE (VulDB): GCVE-100-383090

Entryinfo

Created: 07/25/2026 13:49
Changes: 07/25/2026 13:49 (60)
Complete: 🔍
Cache ID: 216::103

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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