CVE-2025-21948: Linux kernel · NULL Pointer Dereference
Source GCVE Database
Not known to be exploited · CVSS 5.5 Medium.
Data as of 30 Oct 2026, 01:25 UTC
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 1 Apr 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
AI-suggested
A fix is available as the vulnerability has been resolved in the Linux kernel. Users should update to a kernel version that includes this patch. No additional mitigation steps are indicated by the vendor advisory.
Description
CVE-2025-21948 is a vulnerability in the Linux kernel's appleir HID driver that can cause a NULL pointer dereference due to malformed report items from an emulated device. This leads to an event callback being invoked without an associated input device, potentially causing a kernel crash. The issue was discovered by the Linux Verification Center using Syzkaller. A fix involves adding a check for the HID_CLAIMED_INPUT flag to prevent the event hook from proceeding if no input device is claimed.
References
- nvd.nist.gov/vuln/detail/CVE-2025-21948 (opens in a new tab)
- git.kernel.org/stable/c/0df1ac8ee417ad76760ff076faa4518a4d861894 (opens in a new tab)
- git.kernel.org/stable/c/2ff5baa9b5275e3acafdf7f2089f74cccb2f38d1 (opens in a new tab)
- git.kernel.org/stable/c/68cdf6710f228dfd74f66ec61fbe636da2646a73 (opens in a new tab)
- git.kernel.org/stable/c/6db423b00940b05df2a1265d3c7eabafe9f1734c (opens in a new tab)
- git.kernel.org/stable/c/8d39eb8c5e14f2f0f441eed832ef8a7b654e6fee (opens in a new tab)
- git.kernel.org/stable/c/b1d95d733cd6e74f595653daddcfc357bea461e8 (opens in a new tab)
- git.kernel.org/stable/c/d335fce8b88b2353f4bb20c631698e20384e3610 (opens in a new tab)
- git.kernel.org/stable/c/fc69e2c3219d433caabba4b5d6371ba726a4b37f (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/05/msg00030.html (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/05/msg00045.html (opens in a new tab)