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

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.

Affected packages & fixed versions

Affected products (as reported)

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