CVE-2024-46838

userfaultfd: don't BUG_ON() if khugepaged yanks our page table

MEDIUM
5.5
CVSS Score
Published: September 27, 2024 at 12:39 PM UTC
Updated: June 17, 2026 at 07:56 AM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

Description

In the Linux kernel, the following vulnerability has been resolved: userfaultfd: don't BUG_ON() if khugepaged yanks our page table Since khugepaged was changed to allow retracting page tables in file mappings without holding the mmap lock, these BUG_ON()s are wrong - get rid of them. We could also remove the preceding "if (unlikely(...))" block, but then we could reach pte_offset_map_lock() with transhuge pages not just for file mappings but also for anonymous mappings - which would probably be fine but I think is not necessarily expected.

Affected

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

6.6 ≤ v < 6.10.106.6 ≤ v < 6.116.6 ≤ v < 6.6.516.7 ≤ v < 6.10.101d65b771bc08cd054cf6d3766a72e113dc46d62f6.11 rc16.11 rc26.11 rc36.11 rc46.11 rc56.11 rc6
Vendor states this is fixed in 4828d207dc5161dc7ddf9a4f6dcfd80c7dd7d20a (fixed)
Vendor states this is fixed in 4a594acc12d5954cdc71d4450a386748bf3d136a (fixed)
Vendor states this is fixed in db978287e908d48b209e374b00d847b2d785e0a9 (fixed)
Vendor states this is fixed in 6.10.10 (unaffected)
Vendor states this is fixed in 6.11 (unaffected)
Vendor states this is fixed in 6.6 (unaffected)
Vendor states this is fixed in 6.6.51 (unaffected)

References (3)

Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/4828d207dc5161dc7ddf9a4f6dcfd80c7dd7d20a
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/4a594acc12d5954cdc71d4450a386748bf3d136a
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/db978287e908d48b209e374b00d847b2d785e0a9

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

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

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
NVD-CWE-noinfo

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