Bug 2393516 (CVE-2025-39715) - CVE-2025-39715 kernel: parisc: Revise gateway LWS calls to probe user read access
Summary: CVE-2025-39715 kernel: parisc: Revise gateway LWS calls to probe user read ac...
Keywords:
Status: NEW
Alias: CVE-2025-39715
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-09-05 18:03 UTC by OSIDB Bzimport
Modified: 2025-11-26 08:00 UTC (History)
0 users

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


Attachments (Terms of Use)

Description OSIDB Bzimport 2025-09-05 18:03:45 UTC
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.


Note You need to log in before you can comment on or make changes to this bug.