CVE-2025-21864
- Source
- https://nvd.nist.gov/vuln/detail/CVE-2025-21864
- Import Source
- https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-21864.json
- JSON Data
- https://api.test.osv.dev/v1/vulns/CVE-2025-21864
- Downstream
- Related
- Published
- 2025-03-12T09:42:21Z
- Modified
- 2025-10-10T07:53:28.532588Z
- Severity
-
- 5.5 (Medium) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
- Summary
- tcp: drop secpath at the same time as we currently drop dst
- Details
-
In the Linux kernel, the following vulnerability has been resolved:
tcp: drop secpath at the same time as we currently drop dst
Xiumei reported hitting the WARN in xfrm6tunnelnet_exit while running tests that boil down to: - create a pair of netns - run a basic TCP test over ipcomp6 - delete the pair of netns
The xfrmstate found on spibyaddr was not deleted at the time we delete the netns, because we still have a reference on it. This lingering reference comes from a secpath (which holds a ref on the xfrmstate), which is still attached to an skb. This skb is not leaked, it ends up on skreceivequeue and then gets defer-free'd by skbattemptdeferfree.
The problem happens when we defer freeing an skb (push it on one CPU's deferlist), and don't flush that list before the netns is deleted. In that case, we still have a reference on the xfrmstate that we don't expect at this point.
We already drop the skb's dst in the TCP receive path when it's no longer needed, so let's also drop the secpath. At this point, tcp_filter has already called into the LSM hooks that may require the secpath, so it should not be needed anymore. However, in some of those places, the MPTCP extension has just been attached to the skb, so we cannot simply drop all extensions.
- References
-
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- https://git.kernel.org/stable/c/69cafd9413084cd5012cf5d7c7ec6f3d493726d9
- https://git.kernel.org/stable/c/87858bbf21da239ace300d61dd209907995c0491
- https://git.kernel.org/stable/c/9b6412e6979f6f9e0632075f8f008937b5cd4efd
- https://git.kernel.org/stable/c/cd34a07f744451e2ecf9005bb7d24d0b2fb83656
- https://git.kernel.org/stable/c/f1d5e6a5e468308af7759cf5276779d3155c5e98
Affected packages
Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected ranges
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced68822bdf76f10c3dc80609d4e2cdc1e847429086Fixed87858bbf21da239ace300d61dd209907995c0491
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced68822bdf76f10c3dc80609d4e2cdc1e847429086Fixedf1d5e6a5e468308af7759cf5276779d3155c5e98
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced68822bdf76f10c3dc80609d4e2cdc1e847429086Fixedcd34a07f744451e2ecf9005bb7d24d0b2fb83656
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced68822bdf76f10c3dc80609d4e2cdc1e847429086Fixed69cafd9413084cd5012cf5d7c7ec6f3d493726d9
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced68822bdf76f10c3dc80609d4e2cdc1e847429086Fixed9b6412e6979f6f9e0632075f8f008937b5cd4efd