# CVE-2025-39941: linux: In the Linux kernel, the following vulnerability has been resolved:  zram: fix slot write race condition  Parallel co...

CVE-2025-39941 is fixed in linux on 1 platform by DEBIAN-CVE-2025-39941 (version 6.16.9-1), released October 4, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2025-39941
- Priority: Routine
- CVSS: 4.7 (medium)
- EPSS: 0.0010
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 4, 2025

## Description

In the Linux kernel, the following vulnerability has been resolved:  zram: fix slot write race condition  Parallel concurrent writes to the same zram index result in leaked zsmalloc handles.  Schematically we can have something like this:  CPU0                              CPU1 zram_slot_lock() zs_free(handle) zram_slot_lock() 				zram_slot_lock() 				zs_free(handle) 				zram_slot_lock()  compress			compress handle = zs_malloc()		handle = zs_malloc() zram_slot_lock zram_set_handle(handle) zram_slot_lock 				zram_slot_lock 				zram_set_handle(handle) 				zram_slot_lock  Either CPU0 or CPU1 zsmalloc handle will leak because zs_free() is done too early.  In fact, we need to reset zram entry right before we set its new handle, all under the same slot lock scope.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 6.16.9-1 | [DEBIAN-CVE-2025-39941](https://patchblox.com/security/data/fix/linux/debian-cve-2025-39941.md) | Oct 4, 2025 |

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