efivarfs: Fix slab-out-of-bounds in efivarfs_d_compare

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2025-39817
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-09-16 13:15:57 UTC
Updated2026-05-12 13:17:13 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: efivarfs: Fix slab-out-of-bounds in efivarfs_d_compare Observed on kernel 6.6 (present on master as well): BUG: KASAN: slab-out-of-bounds in memcmp+0x98/0xd0 Call trace: kasan_check_range+0xe8/0x190 __asan_loadN+0x1c/0x28 memcmp+0x98/0xd0 efivarfs_d_compare+0x68/0xd8 __d_lookup_rcu_op_compare+0x178/0x218 __d_lookup_rcu+0x1f8/0x228 d_alloc_parallel+0x150/0x648 lookup_open.isra.0+0x5f0/0x8d0 open_last_lookups+0x264/0x828 path_openat+0x130/0x3f8 do_filp_open+0x114/0x248 do_sys_openat2+0x340/0x3c0 __arm64_sys_openat+0x120/0x1a0 If dentry->d_name.len < EFI_VARIABLE_GUID_LEN , 'guid' can become negative, leadings to oob. The issue can be triggered by parallel lookups using invalid filename: T1 T2 lookup_open ->lookup simple_lookup d_add // invalid dentry is added to hash list lookup_open d_alloc_parallel __d_lookup_rcu __d_lookup_rcu_op_compare hlist_bl_for_each_entry_rcu // invalid dentry can be retrieved ->d_compare efivarfs_d_compare // oob Fix it by checking 'guid' before cmp.

Risk And Classification

Primary CVSS: v3.1 7.1 HIGH from [email protected]

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Problem Types: CWE-125

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected da27a24383b2b10bf6ebd0db29b325548aafecb4 0f63fbabeaaaaaaf5b742a2f4c1b4590d50bf1f6 git Not specified
CNA Linux Linux affected da27a24383b2b10bf6ebd0db29b325548aafecb4 794399019301944fd6d2e0d7a51b3327e26c410e git Not specified
CNA Linux Linux affected da27a24383b2b10bf6ebd0db29b325548aafecb4 568e7761279b99c6daa3002290fd6d8047ddb6d2 git Not specified
CNA Linux Linux affected da27a24383b2b10bf6ebd0db29b325548aafecb4 d7f5e35e70507d10cbaff5f9e194ed54c4ee14f7 git Not specified
CNA Linux Linux affected da27a24383b2b10bf6ebd0db29b325548aafecb4 925599eba46045930b850a98ae594d2e3028ac40 git Not specified
CNA Linux Linux affected da27a24383b2b10bf6ebd0db29b325548aafecb4 c2925cd6207079c3f4d040d082515db78d63afbf git Not specified
CNA Linux Linux affected da27a24383b2b10bf6ebd0db29b325548aafecb4 71581a82f38e5a4d807d71fc1bb59aead80ccf95 git Not specified
CNA Linux Linux affected da27a24383b2b10bf6ebd0db29b325548aafecb4 a6358f8cf64850f3f27857b8ed8c1b08cfc4685c git Not specified
CNA Linux Linux affected 688289c4b745c018b3449b4b4c5a2030083c8eaf git Not specified
CNA Linux Linux affected 3.9 Not specified
CNA Linux Linux unaffected 3.9 semver Not specified
CNA Linux Linux unaffected 5.4.298 5.4.* semver Not specified
CNA Linux Linux unaffected 5.10.242 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.191 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.150 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.104 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.45 6.12.* semver Not specified
CNA Linux Linux unaffected 6.16.5 6.16.* semver Not specified
CNA Linux Linux unaffected 6.17 * original_commit_for_fix Not specified
ADP Siemens SIMATIC CN 4100 affected V5.0 custom Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/794399019301944fd6d2e0d7a51b3327e26c410e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
lists.debian.org/debian-lts-announce/2025/10/msg00008.html af854a3a-2127-422b-91ae-364da2661108 lists.debian.org Third Party Advisory
git.kernel.org/stable/c/71581a82f38e5a4d807d71fc1bb59aead80ccf95 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/a6358f8cf64850f3f27857b8ed8c1b08cfc4685c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/0f63fbabeaaaaaaf5b742a2f4c1b4590d50bf1f6 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/d7f5e35e70507d10cbaff5f9e194ed54c4ee14f7 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
cert-portal.siemens.com/productcert/html/ssa-032379.html 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e cert-portal.siemens.com
git.kernel.org/stable/c/c2925cd6207079c3f4d040d082515db78d63afbf 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/925599eba46045930b850a98ae594d2e3028ac40 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/568e7761279b99c6daa3002290fd6d8047ddb6d2 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
lists.debian.org/debian-lts-announce/2025/10/msg00007.html af854a3a-2127-422b-91ae-364da2661108 lists.debian.org Third Party Advisory
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