Vulnerability in Linux
CVE-2025-39941
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.
Vulnerability class: Race Condition
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.001 (0.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 1st percentile — 0.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: -0.000
Affected products
- Linux — versions 71268035f5d734ad6373d953298bd5779985497a, 6.14, 0
- Linux Kernel — versions 6.17
Weakness classification (CWE)
Public proof-of-concept exploits
References
Frequently asked questions
- What is CVE-2025-39941?
- CVE-2025-39941 is a high-severity vulnerability in Linux, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 7.8/10. Published 2025-10-04.
- How severe is CVE-2025-39941?
- High severity. CVSS v3 base score is 7.8 out of 10.
- Is CVE-2025-39941 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.