CVE-2025-38591: bpf: Reject narrower access to pointer ctx fields

mediumCVSS 5.5CVE-2025-38591

CSIRTS triage

vendor: Linux product: Linux KernelOther

What: The eBPF verifier does not properly reject narrower memory access operations on pointer context fields, potentially allowing unsafe access patterns.
Who is affected: Systems running affected Linux kernel versions with eBPF support enabled.
Urgency: Medium severity; not currently exploited but affects kernel security mechanisms.
Action: Update to a patched Linux kernel version that includes the fix for CVE-2025-38591.

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 5.5
Published: 2026-08-06
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-38591

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-2025-385910.19% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 9% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2025-38591	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

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

high[UPDATE] [high] Linux Kernel: Multiple vulnerabilitiescert-bund
unknownexploitedSiemens SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFPcisa
unknownUbuntu Linux Kernel Multiple Vulnerabilitieshkcert

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.

highCVE-2026-74720: In the Linux kernel, the following vulnerability has been resolved: bpf: Preserve pointer stat…nvd · 2026-08-22
highCVE-2026-74715: In the Linux kernel, the following vulnerability has been resolved: bpf: Fix netns reference i…nvd · 2026-08-22
highCVE-2026-74714: In the Linux kernel, the following vulnerability has been resolved: bpf: tcp: Fix use-after-fr…nvd · 2026-08-22
highCVE-2026-74590: In the Linux kernel, the following vulnerability has been resolved: fsverity: Fix bpf_get_fsve…nvd · 2026-08-22
highCVE-2026-74589: In the Linux kernel, the following vulnerability has been resolved: bpf, sockmap: Fix sk_redir…nvd · 2026-08-22
unknownCVE-2026-74400: In the Linux kernel, the following vulnerability has been resolved: bpf: fix crash in bpf_[set…nvd · 2026-08-15