CVE-2025-21768: Linux kernel · Memory Leak
Source GCVE Database
Not known to be exploited · CVSS 5.5 Medium.
Data as of 30 Oct 2026, 16:33 UTC
Thin evidence
One scorer or noneCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 27 Feb 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 30 Oct 2026.
Description
In the Linux kernel, the following vulnerability has been resolved: net: ipv6: fix dst ref loops in rpl, seg6 and ioam6 lwtunnels Some lwtunnels have a dst cache for post-transformation dst. If the packet destination did not change we may end up recording a reference to the lwtunnel in its own cache, and the lwtunnel state will never be freed. Discovered by the ioam6.sh test, kmemleak was recently fixed to catch per-cpu memory leaks. I'm not sure if rpl and seg6 can actually hit this, but in principle I don't see why not.
References
- nvd.nist.gov/vuln/detail/CVE-2025-21768 (opens in a new tab)
- git.kernel.org/stable/c/26f0b472ae2a82920e38c7cf41583951046d586a (opens in a new tab)
- git.kernel.org/stable/c/4c0f200c7d06fedddde82209c099014d63f4a6c0 (opens in a new tab)
- git.kernel.org/stable/c/5ab11a4e219e93b8b31a27f8ec98d42afadd8b7a (opens in a new tab)
- git.kernel.org/stable/c/92191dd1073088753821b862b791dcc83e558e07 (opens in a new tab)
- git.kernel.org/stable/c/e2ef3fa31353b30bda94358fe5205c141289746d (opens in a new tab)