CVE-2026-90018 staging: rtl8723bs: fix OOB read / stack overflow in rtw_get_wps_attr()

What is CVE-2026-90018?

CVE-2026-90018 is a high-severity memory corruption vulnerability in Linux, published on 16 Sep 2026. 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:

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.

Which versions are affected by CVE-2026-90018?

How do I fix CVE-2026-90018?

Apply the vendor's patch.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2026-90018 being exploited?

There is no known exploitation of CVE-2026-90018 in the wild and no public exploit code.

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-101678, BELL-CVE-2026-90018, DEBIAN-CVE-2026-90018, GHSA-jrhx-3qq6-x5q2, UBUNTU-CVE-2026-90018.