CVE-2025-38097

01/Description

In the Linux kernel, the following vulnerability has been resolved: espintcp: remove encap socket caching to avoid reference leak The current scheme for caching the encap socket can lead to reference leaks when we try to delete the netns. The reference chain is: xfrm_state -> enacp_sk -> netns Since the encap socket is a userspace socket, it holds a reference on the netns. If we delete the espintcp state (through flush or individual delete) before removing the netns, the reference on the socket is dropped and the netns is correctly deleted. Otherwise, the netns may not be reachable anymore (if all processes within the ns have terminated), so we cannot delete the xfrm state to drop its reference on the socket. This patch results in a small (~2% in my tests) performance regression. A GC-type mechanism could be added for the socket cache, to clear references if the state hasn't been used "recently", but it's a lot more complex than just not caching the socket.

02/Affected products

linux: linux kernel; debian: debian linux

03/References8

• git.kernel.org/stable/c/028363685bd0b7a19b4a820f82dd905b1dc83999 Patch
• git.kernel.org/stable/c/74fd327767fb784c5875cf7c4ba1217f26020943 Patch
• git.kernel.org/stable/c/9cbca30102028f9ad3d2098f935c4368f581fd07 Patch
• git.kernel.org/stable/c/b58a295d10065960bcb9d60cb8ca6ead9837cd27 Patch
• git.kernel.org/stable/c/e4cde54b46a87231c77256a633be1bef62687d69 Patch
• git.kernel.org/stable/c/9673ca00e6c5503069dc98780e2e89db0e663c16
• git.kernel.org/stable/c/e32bafd08ee35feacd47b05cc5bfe9cd9659cd25
• lists.debian.org/debian-lts-announce/2025/10/msg00008.html Mailing ListThird Party Advisory