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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2025-21864 Detail

Description

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 xfrm6_tunnel_net_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 xfrm_state found on spi_byaddr 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 xfrm_state), which is still attached to an skb. This skb is not leaked, it ends up on sk_receive_queue and then gets defer-free'd by skb_attempt_defer_free. The problem happens when we defer freeing an skb (push it on one CPU's defer_list), and don't flush that list before the netns is deleted. In that case, we still have a reference on the xfrm_state 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.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://cert-portal.siemens.com/productcert/html/ssa-082556.html siemens-SADP
https://git.kernel.org/stable/c/69cafd9413084cd5012cf5d7c7ec6f3d493726d9 kernel.org Patch 
https://git.kernel.org/stable/c/87858bbf21da239ace300d61dd209907995c0491 kernel.org Patch 
https://git.kernel.org/stable/c/9b6412e6979f6f9e0632075f8f008937b5cd4efd kernel.org Patch 
https://git.kernel.org/stable/c/cd34a07f744451e2ecf9005bb7d24d0b2fb83656 kernel.org Patch 
https://git.kernel.org/stable/c/f1d5e6a5e468308af7759cf5276779d3155c5e98 kernel.org Patch 
https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html CVE

Weakness Enumeration

CWE-ID CWE Name Source
CWE-476 NULL Pointer Dereference cwe source acceptance level NIST   CISA-ADP  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

8 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2025-21864
NVD Published Date:
03/12/2025
NVD Last Modified:
06/17/2026
Source:
kernel.org