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CVE-2025-39855: linux kernel vulnerability
CVE-2025-39855: high vulnerability affecting linux kernel. Check CVSS, KEV status, business impact and recommended administrator actions.
- CVSS
- 7.8 HIGH
- EPSS
- 4.83%
- Known exploited
- not in KEV
- Product
- linux kernel
What is known
In the Linux kernel, the following vulnerability has been resolved: ice: fix NULL access of tx->in_use in ice_ptp_ts_irq The E810 device has support for a "low latency" firmware interface to access and read the Tx timestamps. This interface does not use the standard Tx timestamp logic, due to the latency overhead of proxying sideband command requests over the firmware AdminQ. The logic still makes use of the Tx timestamp tracking structure, ice_ptp_tx, as it uses the same "ready" bitmap to track which Tx timestamps complete. Unfortunately, the ice_ptp_ts_irq() function does not check if the tracker is initialized before its first access. This results in NULL dereference or use-after-free bugs similar to the following: [245977.278756] BUG: kernel NULL pointer dereference, address: 0000000000000000 [245977.278774] RIP: 0010:_find_first_bit+0x19/0x40 [245977.278796] Call Trace: [245977.278809] ? ice_misc_intr+0x364/0x380 [ice] This can occur if a Tx timestamp interrupt races with the driver reset logic. Fix this by only checking the in_use bitmap (and other fields) if the tracker is marked as initialized. The reset flow will clear the init field under lock before it tears the tracker down, thus preventing any use-after-free or NULL access.
Business impact
Successful exploitation of CVE-2025-39855, a high vulnerability (CVSS 7.8) affecting linux kernel, may affect the confidentiality, integrity or availability of the vulnerable environment. The exact impact depends on the installed version, exposed interfaces and deployment configuration.
Recommended administrator action
Confirm whether linux kernel is present and compare installed versions with the vendor advisory and NVD record. Apply the vendor patch or documented mitigation; until remediation is complete, reduce exposure of affected interfaces, review relevant logs and monitor for indicators of exploitation. DataHouse can support version verification, managed patching, network exposure reduction, log review and backup validation for dedicated, cloud and colocated environments.