CVE-2026-23364
Timing Attack Vulnerability in Linux ksmbd MAC Comparison
Publication date: 2026-03-25
Last updated on: 2026-04-24
Assigner: kernel.org
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | 5.15 |
| linux | linux_kernel | From 6.19 (inc) to 6.19.7 (exc) |
| linux | linux_kernel | 7.0 |
| linux | linux_kernel | 7.0 |
| linux | linux_kernel | 7.0 |
| linux | linux_kernel | 7.0 |
| linux | linux_kernel | 7.0 |
| linux | linux_kernel | 7.0 |
| linux | linux_kernel | 7.0 |
| linux | linux_kernel | From 6.2 (inc) to 6.6.130 (exc) |
| linux | linux_kernel | From 5.15.1 (inc) to 6.1.167 (exc) |
| linux | linux_kernel | From 6.13 (inc) to 6.18.19 (exc) |
| linux | linux_kernel | From 6.7 (inc) to 6.12.78 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability in the Linux kernel involves the ksmbd component where Message Authentication Codes (MACs) were compared using a standard memory comparison function (memcmp()). This approach is vulnerable to timing attacks because the time taken to compare MACs can vary depending on the data, potentially leaking information.
The fix replaces memcmp() with crypto_memneq(), a function designed to perform MAC comparisons in constant time, preventing attackers from gaining information through timing analysis.
How can this vulnerability impact me? :
This vulnerability can allow attackers to perform timing attacks to infer the correct MAC values by measuring the time taken to compare MACs. This could lead to unauthorized access or data tampering if an attacker successfully forges valid MACs.
By exploiting this, attackers might bypass authentication or integrity checks, potentially compromising system security.
What immediate steps should I take to mitigate this vulnerability?
The vulnerability is resolved by updating the Linux kernel to a version where the ksmbd component uses constant-time MAC comparison by replacing memcmp() with crypto_memneq().
Therefore, the immediate mitigation step is to update your Linux kernel to the fixed version that includes this patch.