CVE-2025-39716 parisc: Revise __get_user() to probe user read access
A flaw in the Linux kernel parisc architecture allows user code to access read-protected memory via system calls, potentially leading to privilege escalation or data exposure.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-39716?
CVE-2025-39716 is a medium-severity vulnerability in Debian Debian Linux, published on 5 Sep 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Which versions are affected by CVE-2025-39716?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2025-39716?
Apply the vendor's patch.
Is CVE-2025-39716 being exploited?
There is no known exploitation of CVE-2025-39716 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as AZL-67013, AZL-73662, BELL-CVE-2025-39716, DEBIAN-CVE-2025-39716, GHSA-pv37-x56g-xg2m, ROOT-OS-DEBIAN-11-CVE-2025-39716 and 5 more.