CVE-2026-74589: bpf, sockmap: Fix sk_redir use-after-free in send verdict

mediumCVSS 4.1CVE-2026-74589

CSIRTS triage

vendor: Linux product: Linux Kernel Memory corruption

What: A use-after-free vulnerability exists in the BPF sockmap send verdict code where sk_redir may be accessed after it is freed.
Who is affected: Systems with BPF and sockmap enabled, particularly those using eBPF-based networking policies.
Urgency: Medium priority; requires specific BPF program configuration to trigger but can cause kernel crash.
Action: Apply kernel patches addressing CVE-2026-74589 when available through distribution updates.

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

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: medium — CVSS 4.1
Published: 2026-08-11
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-74589

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-2026-745890.18% 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-2026-74589	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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

Recent advisories for bpf, sockmap

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.

highCVE-2026-74589: In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: Fix sk_redir…nvd · 2026-08-22
highCVE-2026-74257: In the Linux kernel, the following vulnerability has been resolved: sockmap: Fix use-after-fre…nvd · 2026-08-15
highCVE-2026-74256: In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: fix integer …nvd · 2026-08-15
mediumCVE-2026-68386: bpf, sockmap: Reject unhashed UDP sockets on sockmap updatemsrc · 2026-08-11
highCVE-2026-74257: sockmap: Fix use-after-free in udp_bpf_recvmsg()msrc · 2026-08-11
highCVE-2026-68284: bpf, sockmap: Fix cork use-after-free in tcp_bpf_sendmsg()msrc · 2026-08-11