{"id":"CVE-2026-90018","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-90018","summary":"staging: rtl8723bs: fix OOB read / stack overflow in rtw_get_wps_attr()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nstaging: rtl8723bs: fix OOB read / stack overflow in rtw_get_wps_attr()\n\nrtw_get_wps_attr() walks WPS attributes inside a WPS IE taken from\na wireless management frame. For each candidate attribute it only\nchecks that the fixed 4-byte attribute header (2-byte ID + 2-byte\nlength) fits inside the IE:\n\n\tif (attr_ptr + 4 > wps_ie + wps_ielen)\n\t\tbreak;\n\tu16 attr_id = get_unaligned_be16(attr_ptr);\n\tu16 attr_data_len = get_unaligned_be16(attr_ptr + 2);\n\tu16 attr_len = attr_data_len + 4;\n\nattr_data_len (and therefore attr_len) is read directly from the\nwire and is never checked against the remaining bytes in the IE\nbefore being used as the size of:\n\n\tmemcpy(buf_attr, attr_ptr, attr_len);\n\nSince attr_len is fully attacker controlled (0 to 65535+4), this is\nboth a heap OOB read of wps_ie, and, more seriously, a stack buffer\noverflow at several call sites where buf_attr is a single-byte\nstack variable, e.g. rtw_get_wps_attr_content()'s callers passing\nWPS_ATTR_SELECTED_REGISTRAR into a stack \"u8 sr\"/\"u8\nselected_registrar\" (drivers/staging/rtl8723bs/os_dep/ioctl_cfg80211.c,\ndrivers/staging/rtl8723bs/core/rtw_mlme_ext.c). A crafted WPS IE in a\nbeacon or probe response processed during scanning can therefore\nsmash the stack of the parsing thread.\n\nrtw_get_wps_attr_content() itself has no independent length check\nand simply trusts the attr_len it gets back from rtw_get_wps_attr(),\nso fixing the bound here also fixes that caller.\n\nThe \"attr_ptr + 4 > wps_ie + wps_ielen\" header check above was added\nby commit 1463ca3ec6601 (\"staging: rtl8723bs: fix OOB reads in\nrtw_get_sec_ie(), rtw_get_wapi_ie(), and rtw_get_wps_attr()\"), which\nbounded the fixed header but never extended the check to cover the\nvariable-length attribute data that follows it. Add that missing\ncheck before attr_len is used as a memcpy() length or accepted as a\nmatch.","published":"2026-09-16T10:33:23.489Z","modified":"2026-09-17T03:47:20.448139446Z","cvss":{"score":8.8,"severity":"HIGH","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"5.15.221"}],"fix":null,"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/34f51d196c43a42046d229de5e79025d5ca553ca"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3a6457ebf39080b87c712657fdb38f34a24fc3ff"},{"type":"WEB","url":"https://git.kernel.org/stable/c/931640dfcb8cfa08f6cfb46229716d8072356420"},{"type":"WEB","url":"https://git.kernel.org/stable/c/99aa998dec83ba180822f70e6d48a514fc81c20d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a53d1ac9ce63db07943b2b2248111003851fb00f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/fd5e24ea8373347d0352f153a66e8647337d1b10"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ff61aa3289355dafa811550a1764691cd1f5d33b"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90018.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90018"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-17T03:47:20.448139446Z"}}