CVE-2025-39715: In the Linux kernel, the following vulnerability has been resolved: parisc: Revise gateway LWS calls to probe user read access We use load and stbys...

Description

In the Linux kernel, the following vulnerability has been resolved: parisc: Revise gateway LWS calls to probe user read access We use load and stbys,e instructions to trigger memory reference interruptions without writing to memory. Because of the way read access support is implemented, read access interruptions are only triggered at privilege levels 2 and 3. The kernel and gateway page execute at privilege level 0, so this code never triggers a read access interruption. Thus, it is currently possible for user code to execute a LWS compare and swap operation at an address that is read protected at privilege level 3 (PRIV_USER). Fix this by probing read access rights at privilege level 3 and branching to lws_fault if access isn't allowed.

Metrics

CVSS 3.1

5.5/10

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

EPSS Probability

0.14%

3.3th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Linux	Linux Kernel	>= 5.17, < 6.1.149
Linux	Linux Kernel	>= 6.2, < 6.6.103
Linux	Linux Kernel	>= 6.7, < 6.12.44
Linux	Linux Kernel	>= 6.13, < 6.16.4
Debian	Debian Linux	11.0

References

Timeline

Published: Sep 5, 2025
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2025-39715?

In the Linux kernel, the following vulnerability has been resolved: parisc: Revise gateway LWS calls to probe user read access We use load and stbys,e instructions to trigger memory reference interruptions without writing to memory. Because of the way read access support is implemented, read access interruptions are only triggered at privilege levels 2 and 3. The kernel and gateway page execute at privilege level 0, so this code never triggers a read access interruption. Thus, it is currently possible for user code to execute a LWS compare and swap operation at an address that is read protected at privilege level 3 (PRIV_USER). Fix this by probing read access rights at privilege level 3 and branching to lws_fault if access isn't allowed.

How severe is CVE-2025-39715?

CVE-2025-39715 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.14% probability of exploitation in the next 30 days.

How do I fix CVE-2025-39715?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.