CVE-2026-74692: net/smc: fix TOCTOU race between smc_listen_out() and listener close

mediumCVSS 5.9CVE-2026-74692

CSIRTS triage

vendor: Linux product: Linux kernel Memory corruption

What: SMC (Shared Memory Communications) has a TOCTOU race condition between smc_listen_out() and listener socket close, leading to use-after-free.
Who is affected: Systems using SMC protocol for low-latency communication with concurrent listening and close operations.
Urgency: Medium priority; CVSS 5.9 indicates moderate severity; not currently exploited but race condition can cause crashes.
Action: Apply kernel patch serializing smc_listen_out() and listener close operations or update to patched version.

AI-assisted analysis generated from the source advisory — verify against the original.

⚡ Watch Linux kernel

Get an email when a new Linux kernel advisory drops — max one per day, one-click unsubscribe.

Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: medium — CVSS 5.9
Published: 2026-08-11
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-74692

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-746920.17% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 7% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-74692	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

highCVE-2026-74692: In the Linux kernel, the following vulnerability has been resolved: net/smc: fix TOCTOU race b…nvd

Recent advisories for net/smc

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

unknownCVE-2026-74719: In the Linux kernel, the following vulnerability has been resolved: net/smc: fix qentry overwr…nvd · 2026-08-22
highCVE-2026-74692: In the Linux kernel, the following vulnerability has been resolved: net/smc: fix TOCTOU race b…nvd · 2026-08-22
criticalCVE-2026-74493: In the Linux kernel, the following vulnerability has been resolved: net/smc: fix socket use-af…nvd · 2026-08-15
lowCVE-2026-74719: net/smc: fix qentry overwrite for CONFIRM_LINK and ADD_LINK_CONT in smc_llc_event_handler()msrc · 2026-08-11
mediumCVE-2026-74493: net/smc: fix socket use-after-free during link group terminationmsrc · 2026-08-11
mediumCVE-2024-56641: net/smc: initialize close_work early to avoid warningmsrc · 2026-08-06