CVE-2025-39836

efi: stmm: Fix incorrect buffer allocation method

HIGH
7.8
CVSS Score
Published: September 16, 2025 at 01:08 PM UTC
Updated: October 19, 2026 at 09:10 PM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
HIGH7.8
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

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().

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

6.13 ≤ v < 6.16.56.8 ≤ v < 6.12.456.176.17 rc16.17 rc26.17 rc36.8c44b6be62e8dd4ee0a308c36a70620613e6fc55f
Vendor states this is fixed in 630c0e6064daf84f17aad1a7d9ca76b562e3fe47 (fixed)
Vendor states this is fixed in 77ff27ff0e4529a003c8a1c2492c111968c378d3 (fixed)
Vendor states this is fixed in c5e81e672699e0c5557b2b755cc8f7a69aa92bff (fixed)
Vendor states this is fixed in 6.12.45 (unaffected)
Vendor states this is fixed in 6.16.5 (unaffected)
Vendor states this is fixed in 6.17 (unaffected)
Vendor states this is fixed in 6.8 (unaffected)

References (3)

Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/630c0e6064daf84f17aad1a7d9ca76b562e3fe47
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/77ff27ff0e4529a003c8a1c2492c111968c378d3
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/c5e81e672699e0c5557b2b755cc8f7a69aa92bff

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.8HIGHLinux
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-787

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