Medium

Linux kernel BPF rcu_read_lock_trace check flaw in bpf_map_lookup_percpu_elem

IdentifiersCVE-2025-38202CWE-754

CVE-2025-38202 is a Linux kernel BPF vulnerability in the handling of bpf_map_lookup_percpu_elem() when used from sleepable BPF programs. The helper is available to sleepable BPF program types, but when BPF JIT is disabled or the system is running on a 32-bit host, the helper is not inlined and executes a lock-state validation path that only checked for the regular RCU read-side lock. Sleepable BPF programs instead hold the trace RCU read lock, causing the helper to incorrectly conclude that the required lock was not held and emit a kernel warning. The fix adds the missing rcu_read_lock_trace_held() check so the helper correctly recognizes the locking context used by sleepable BPF programs.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful triggering of the flaw can cause kernel warning conditions during execution of affected sleepable BPF programs that call bpf_map_lookup_percpu_elem() in the affected environments. Based on the available information, the primary security impact is denial of service or operational instability through WARN-triggered fault conditions rather than arbitrary code execution or direct privilege escalation. No evidence is provided that the issue enables memory corruption or confidentiality compromise.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce exposure by restricting the ability to load or run untrusted sleepable BPF programs, especially on systems where BPF JIT is disabled or on 32-bit hosts. Minimizing access to BPF capabilities for non-administrative users and limiting use of affected BPF helper paths can reduce the likelihood of triggering the warning condition. No specific complete workaround is available from the provided information other than applying a fixed kernel.

Remediation

Patch, then assume compromise.

Update to a Linux kernel release that includes the fix for CVE-2025-38202, specifically the change that adds rcu_read_lock_trace_held() validation in bpf_map_lookup_percpu_elem(). Vendor kernel security updates addressing this CVE are available from multiple distributors, including Red Hat, Ubuntu, and SUSE. A system reboot is typically required after installing the updated kernel for the fix to take effect.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

DebianDebian Linuxoperating_system

LinuxLinux Kerneloperating_system

SuseLinux Enterprise Server 15 Sp6 Azure Kerneloperating_system

SuseLinux Kerneloperating_system

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

5 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

5 SOURCESView more in app

redhat accessNews

May 19, 2026

RHSA-2026:18134 - Security Advisory - Red Hat Customer Portal

Linux kernel BPF vulnerability related to missing rcu_read_lock_trace_held() checking in bpf_map_lookup_percpu_elem().

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Exposure mapping

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Threat actor evidence

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Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

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Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity1