# CVE-2025-37923: tracing: Fix oob write in trace_seq_to_buffer()

> A local attacker can trigger an out-of-bounds write in the Linux kernel tracing subsystem, potentially leading to code execution or privilege escalation.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 20 May 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2025-37923, DEBIAN-CVE-2025-37923, GHSA-g586-9cjh-f4c9, ROOT-OS-DEBIAN-11-CVE-2025-37923, ROOT-OS-DEBIAN-12-CVE-2025-37923, ROOT-OS-UBUNTU-2204-CVE-2025-37923, ROOT-OS-UBUNTU-2404-CVE-2025-37923, UBUNTU-CVE-2025-37923

## What is CVE-2025-37923?

CVE-2025-37923 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 20 May 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

tracing: Fix oob write in trace_seq_to_buffer()

syzbot reported this bug:
==================================================================
BUG: KASAN: slab-out-of-bounds in trace_seq_to_buffer kernel/trace/trace.c:1830 [inline]
BUG: KASAN: slab-out-of-bounds in tracing_splice_read_pipe+0x6be/0xdd0 kernel/trace/trace.c:6822
Write of size 4507 at addr ffff888032b6b000 by task syz.2.320/7260

CPU: 1 UID: 0 PID: 7260 Comm: syz.2.320 Not tainted 6.15.0-rc1-syzkaller-00301-g3bde70a2c827 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xc3/0x670 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189
 __asan_memcpy+0x3c/0x60 mm/kasan/shadow.c:106
 trace_seq_to_buffer kernel/trace/trace.c:1830 [inline]
 tracing_splice_read_pipe+0x6be/0xdd0 kernel/trace/trace.c:6822
 ....
==================================================================

It has been reported that trace_seq_to_buffer() tries to copy more data
than PAGE_SIZE to buf. Therefore, to prevent this, we should use the
smaller of trace_seq_used(&iter->seq) and PAGE_SIZE as an argument.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2025-37923?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-37923?

Apply the vendor's patch.

## Is CVE-2025-37923 being exploited?

There is no known exploitation of CVE-2025-37923 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-37923 and fix it if it is affected.

What it is: CVE-2025-37923 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 20 May 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-37923 in the wild and no public exploit code.

Affected product: Debian Debian Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-37923/ (Markdown: https://insights.sbomify.com/CVE-2025-37923/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-37923
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-37923
- OSV: https://osv.dev/vulnerability/CVE-2025-37923

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-37923/
Summaries are generated and may contain mistakes; the official description above is the record.