CVE-2026-43009: bpf: Fix incorrect pruning due to atomic fetch precision tracking

highCVSS 7.8CVE-2026-43009

CSIRTS triage

vendor: Linux product: Linux kernel Privilege escalation

What: BPF verifier contains incorrect pruning logic due to imprecise atomic fetch operation tracking, allowing bypass of safety checks.
Who is affected: Systems running Linux kernel with BPF programs from untrusted sources or unprivileged BPF access enabled.
Urgency: High priority; allows privilege escalation through BPF verifier bypass without requiring root initially.
Action: Update to a patched Linux kernel version with corrected BPF atomic fetch precision tracking.

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: high — CVSS 7.8
Published: 2026-08-06
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-43009

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-2026-430090.13% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 3% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-43009	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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

unknownMultiple vulnerabilities in the SUSE Linux kernel (June 26, 2026)cert-fr-avis

Recent advisories for bpf

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.

mediumCVE-2024-56665: bpf,perf: Fix invalid prog_array access in perf_event_detach_bpf_progmsrc · 2026-08-06
mediumCVE-2026-23383: bpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearingmsrc · 2026-08-06
mediumCVE-2025-37959: bpf: Scrub packet on bpf_redirect_peermsrc · 2026-08-06
mediumCVE-2024-42151: bpf: mark bpf_dummy_struct_ops.test_1 parameter as nullablemsrc · 2026-08-06
highCVE-2026-45932: bpf: Fix tcx/netkit detach permissions when prog fd isn't givenmsrc · 2026-08-06
mediumCVE-2024-42067: bpf: Take return from set_memory_rox() into account with bpf_jit_binary_lock_ro()msrc · 2026-08-06