CVE-2025-39836

efi: stmm: Fix incorrect buffer allocation method

State: Published
Severity: 7.8 High
Published: Sep 16, 2025
Updated: Aug 5, 2026
Reserved: Apr 16, 2025

Description

In the Linux kernel, the following vulnerability has been resolved:

efi: stmm: Fix incorrect buffer allocation method

The communication buffer allocated by setup_mm_hdr() is later on passed to tee_shm_register_kernel_buf(). The latter expects those buffers to be contiguous pages, but setup_mm_hdr() just uses kmalloc(). That can cause various corruptions or BUGs, specifically since commit 9aec2fb0fd5e ("slab: allocate frozen pages"), though it was broken before as well.

Fix this by using alloc_pages_exact() instead of kmalloc().

Scores

CVSS	Score	Vector	Source
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	Linux
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	CISA-ADP

Weaknesses

CWE-787 Out-of-bounds Write

Affected Products

Product	Versions
LinuxLinux	c44b6be62e8dd4ee0a308c36a70620613e6fc55f to before 77ff27ff0e4529a003c8a1c2492c111968c378d3Affected c44b6be62e8dd4ee0a308c36a70620613e6fc55f to before 630c0e6064daf84f17aad1a7d9ca76b562e3fe47Affected c44b6be62e8dd4ee0a308c36a70620613e6fc55f to before c5e81e672699e0c5557b2b755cc8f7a69aa92bffAffected
LinuxLinux	6.8Affected before 6.8Not affected 6.12.45 through 6.12.Not affected 6.16.5 through 6.16.Not affected 6.17 and laterNot affected

References

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