PatchSiren

PatchSiren cyber security CVE debrief

CVE-2026-63936 Linux CVE debrief

The Linux kernel was vulnerable to an unchecked return value issue in the mt6359 driver, which could lead to unpredictable measurement results or potential stack data leakage if a read operation failed. The vulnerability is now resolved, and Linux kernel users and maintainers should be aware of this issue to ensure they are using the patched version. The vulnerability has been resolved by initializing val_v to zero in the mt6358_read_imp() function. This change ensures a predictable value is reported in case of bus failure and prevents potential stack data leakage.

Vendor
Linux
Product
Unknown
CVSS
Unknown
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-19
Original CVE updated
2026-07-19
Advisory published
2026-07-19
Advisory updated
2026-07-19

Who should care

Linux kernel users and maintainers should be aware of this vulnerability and ensure they are using the patched version to prevent potential issues. Users of the Linux kernel should review the official advisory to determine if their systems are affected and take necessary actions to update the kernel. Security teams should also be aware of this vulnerability and monitor for any potential issues related to the mt6359 driver.

Technical summary

In the Linux kernel, the mt6358_read_imp() function did not check the return value of regmap_read(). If the read failed, the variable val_v would remain uninitialized, potentially leading to stack data leakage or incorrect measurement results. The issue has been resolved by initializing val_v to zero, ensuring a predictable value is reported in case of bus failure and preventing potential stack data leakage. This change satisfies static analyzers that might otherwise flag the variable as used uninitialized.

Defensive priority

Medium

Recommended defensive actions

  • Apply the patch to initialize val_v to zero in mt6358_read_imp()
  • Ensure Linux kernel is updated to the latest version
  • Monitor for any potential issues related to the mt6359 driver
  • Review the official advisory to determine if systems are affected
  • Verify the patched version is being used
  • Track exceptions and retest remediated assets
  • Confirm whether affected product deployments exist in managed environments

Evidence notes

The CVE record was published on 2026-07-19T16:17:12.080Z and has not been modified since then. The NVD entry is currently Received. There is limited information available about the vulnerability, and defenders should verify the affected scope and severity with the official advisory. The vulnerability is resolved in the Linux kernel, and users should ensure they are using the patched version to prevent potential issues. The CVE record does not provide additional details about the vulnerability, and defenders should review the official advisory for more information.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-19T16:17:12.080Z and has not been modified since then.