# CVE-2025-39716: parisc: Revise __get_user() to probe user read access

CVE-2025-39716 is fixed in linux on 1 platform, first by DEBIAN-CVE-2025-39716, released September 5, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2025-39716
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0016
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 5, 2025
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-39716

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.153-1 | [DEBIAN-CVE-2025-39716](https://patchblox.com/security/data/fix/linux/debian-cve-2025-39716.md) | Sep 5, 2025 |
| Linux | linux Debian 13.5 (trixie) | 6.12.48-1 | [DEBIAN-CVE-2025-39716](https://patchblox.com/security/data/fix/linux/debian-cve-2025-39716.md) | Sep 5, 2025 |
| Linux | linux Debian 14 | 6.16.5-1 | [DEBIAN-CVE-2025-39716](https://patchblox.com/security/data/fix/linux/debian-cve-2025-39716.md) | Sep 5, 2025 |

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