CVE-2025-39716

parisc: Revise __get_user() to probe user read access

MEDIUM
5.5
CVSS Score
Published: September 5, 2025 at 05:21 PM UTC
Updated: October 19, 2026 at 09:10 PM UTC
3 products affected across 3 vendorsLinux KernelDebian LinuxSIMATIC CN 4100

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.1%

Description

In the Linux kernel, the following vulnerability has been resolved: parisc: Revise __get_user() to probe user read access Because of the way read access support is implemented, read access interruptions are only triggered at privilege levels 2 and 3. The kernel executes at privilege level 0, so __get_user() never triggers a read access interruption (code 26). Thus, it is currently possible for user code to access a read protected address via a system call. Fix this by probing read access rights at privilege level 3 (PRIV_USER) and setting __gu_err to -EFAULT (-14) if access isn't allowed. Note the cmpiclr instruction does a 32-bit compare because COND macro doesn't work inside asm.

Affected

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

2.6.13 ≤ v < 6.1.1496.13 ≤ v < 6.16.46.2 ≤ v < 6.6.1036.7 ≤ v < 6.12.441da177e4c3f41524e886b7f1b8a0c1fc7321cac22.6.122.6.12 rc22.6.12 rc32.6.12 rc42.6.12 rc5
Vendor states this is fixed in 28a9b71671fb4a2993ef85b8ef6f117ea63894fe (fixed)
Vendor states this is fixed in 4c981077255acc2ed5b3df6e8dd0125c81b626a9 (fixed)
Vendor states this is fixed in 741b163e440683195b8fd4fc8495fcd0105c6ab7 (fixed)
Vendor states this is fixed in 89f686a0fb6e473a876a9a60a13aec67a62b9a7e (fixed)
Vendor states this is fixed in f410ef9a032caf98117256b22139c31342d7bb06 (fixed)
Vendor states this is fixed in 2.6.12 (unaffected)
Vendor states this is fixed in 6.1.149 (unaffected)
Vendor states this is fixed in 6.12.44 (unaffected)
Vendor states this is fixed in 6.16.4 (unaffected)
Vendor states this is fixed in 6.17 (unaffected)
Vendor states this is fixed in 6.6.103 (unaffected)
v < V5.0
Affected range stops below V5.0, so it looks safe — our inference, not a vendor statement

References (7)

Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/28a9b71671fb4a2993ef85b8ef6f117ea63894fe
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/4c981077255acc2ed5b3df6e8dd0125c81b626a9
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/741b163e440683195b8fd4fc8495fcd0105c6ab7
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/89f686a0fb6e473a876a9a60a13aec67a62b9a7e
Patch
Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
https://git.kernel.org/stable/c/f410ef9a032caf98117256b22139c31342d7bb06
Third Party Advisory
Source: af854a3a-2127-422b-91ae-364da2661108
https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
Source: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
https://cert-portal.siemens.com/productcert/html/ssa-032379.html

CVSS

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

Quick Info

StatusMODIFIED
CWE
NVD-CWE-noinfo

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