Cyber Resilience

CVE-2025-38493

DoS in Linux Kernel 6.6 – 6.6.100

Published
28 July 2025
Modified
17 June 2026
Patch / advisory
CVSS Score v3.1 5.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0015 5th percentile
Risk Priority 41 floored blend · peak EPSS

Summary

CVE-2025-38493 is a medium-severity Uncontrolled Recursion (CWE-674) vulnerability in Linux Linux Kernel. Its CVSS base score is 5.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked at the 5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and SC-5 (Denial-of-service Protection) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

In the Linux kernel, the following vulnerability has been resolved: tracing/osnoise: Fix crash in timerlat_dump_stack() We have observed kernel panics when using timerlat with stack saving, with the following dmesg output: memcpy: detected buffer overflow: 88 byte write of buffer…

more

size 0 WARNING: CPU: 2 PID: 8153 at lib/string_helpers.c:1032 __fortify_report+0x55/0xa0 CPU: 2 UID: 0 PID: 8153 Comm: timerlatu/2 Kdump: loaded Not tainted 6.15.3-200.fc42.x86_64 #1 PREEMPT(lazy) Call Trace: <TASK> ? trace_buffer_lock_reserve+0x2a/0x60 __fortify_panic+0xd/0xf __timerlat_dump_stack.cold+0xd/0xd timerlat_dump_stack.part.0+0x47/0x80 timerlat_fd_read+0x36d/0x390 vfs_read+0xe2/0x390 ? syscall_exit_to_user_mode+0x1d5/0x210 ksys_read+0x73/0xe0 do_syscall_64+0x7b/0x160 ? exc_page_fault+0x7e/0x1a0 entry_SYSCALL_64_after_hwframe+0x76/0x7e __timerlat_dump_stack() constructs the ftrace stack entry like this: struct stack_entry *entry; ... memcpy(&entry->caller, fstack->calls, size); entry->size = fstack->nr_entries; Since commit e7186af7fb26 ("tracing: Add back FORTIFY_SOURCE logic to kernel_stack event structure"), struct stack_entry marks its caller field with __counted_by(size). At the time of the memcpy, entry->size contains garbage from the ringbuffer, which under some circumstances is zero, triggering a kernel panic by buffer overflow. Populate the size field before the memcpy so that the out-of-bounds check knows the correct size. This is analogous to __ftrace_trace_stack().

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-38315Same product: Linux Linux Kernel
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CVE-2026-43080Same product: Linux Linux Kernel
CVE-2026-53329Same product: Linux Linux Kernel
CVE-2025-40090Same product: Linux Linux Kernel
CVE-2026-43185Same product: Linux Linux Kernel
CVE-2026-53202Same product: Linux Linux Kernel
CVE-2026-53267Same product: Linux Linux Kernel

Affected Assets

linux
linux kernel
6.16 · 6.6 — 6.6.100 · 6.7 — 6.12.40 · 6.13 — 6.15.8

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

Input validation can reject or constrain data that would otherwise drive unbounded recursive calls.

DoS protection mechanisms limit the resource-exhaustion impact of uncontrolled recursion without eliminating the flaw.

System monitoring can observe anomalous resource consumption that signals runaway recursion after it begins.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly prevent coding errors such as missing recursion limits or termination conditions.

DE.CM-09 partial match
prevents

Runtime monitoring of compute resources can detect excessive consumption caused by uncontrolled recursion.

ID.RA-01 partial match
prevents

Vulnerability identification processes can discover and record uncontrolled recursion flaws before deployment.

PR.IR-04 partial match
prevents

Capacity monitoring and resource provisioning can absorb or limit the impact of runaway recursion.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing in development can detect excessive recursion via static analysis or fuzzing.

prevents

Secure development life cycle requires controls that prevent uncontrolled recursion through design and code review.

prevents

Application security requirements can mandate recursion limits or stack-depth checks.

prevents

Secure system architecture principles include resource-management and input-validation rules that limit recursion.

prevents

Secure coding standards directly prohibit or constrain recursive constructs that could exhaust stack or memory.

finds

Capacity management includes monitoring and limits that mitigate resource exhaustion from runaway recursion.

References