CVE-2026-80979

Received Received - Intake

Linux Kernel SMC Connection Handling Race Condition

Publication date: 2026-09-11

Last updated on: 2026-09-14

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: net/smc: unregister the connection before draining the rx tasklet smc_conn_free() calls smc_ism_unset_conn() only while the link group is still on its device list, and never sets conn->killed. smc_lgr_terminate_sched() unlinks the group immediately and defers killing its connections to a work item, so a connection freed in that window keeps its smcd->conn[] slot with both gates in smcd_handle_irq() open, and the device can re-arm the receive tasklet after tasklet_kill() has returned. On the DMB-nocopy path the ghost send buffer is freed right after that drain, so the re-armed tasklet dereferences it. Unregister unconditionally and drain before the detach at both teardown sites, mirroring rmb_desc, which smc_buf_unuse() releases after the drain. Clear conn->sndbuf_desc before freeing it as well, so a reader that samples the pointer cannot get one that is already freed.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-09-11

Last Modified

2026-09-14

Generated

2026-10-02

AI Q&A

2026-09-12

EPSS Evaluated

2026-09-29

NVD

CVE-2026-80979

EUVD

EUVD-2026-76302

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves improper handling of network connections during teardown. The issue occurs when a connection is freed before properly unregistering it and draining the receive tasklet, which can lead to a use-after-free scenario where the tasklet dereferences a freed memory buffer.

Detection Guidance

This vulnerability is specific to the Linux kernel's SMC (Socket Direct) implementation and involves race conditions in connection handling. Detection requires kernel-level inspection and may not have direct user-space commands. Monitor kernel logs for smc-related errors or crashes, especially during network disconnections or tasklet operations. Check for kernel oops or warnings related to smc_conn_free or smc_lgr_terminate_sched.

Impact Analysis

This vulnerability could allow an attacker to cause a denial-of-service condition or potentially execute arbitrary code on affected systems by triggering the improper cleanup sequence. Systems using the Linux kernel with SMC (Socket Messaging over RDMA) functionality may be vulnerable.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards as it pertains to a memory management issue in the Linux kernel's SMC (Socket Messaging over RDMA) subsystem. No evidence suggests data exposure or privacy violations that would impact regulatory compliance.

Mitigation Strategies

Update the Linux kernel to the latest patched version to resolve this vulnerability. Monitor kernel security advisories for patches addressing CVE-2026-80979.

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