{"id":"CVE-2026-98711","kind":"vulnerability","aliases":["CVE-2026-98711"],"related":[],"title":"Linux kernel: cw1200 Wi-Fi driver leaks heap bytes to its device","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: cw1200: fix TX padding OOB read leaking heap data to device\n\nThe TX path rounds the transfer size up to the bus alignment\n(align_size(), up to 511 bytes for SDIO, 1 byte for SPI) but sends\nthe padded length straight from the frame buffer, which has no room\nreserved for the padding.  cw1200_data_write() therefore reads past\nthe end of the frame and the bus transfer carries those bytes to the\ndevice.  A bogus device can collect up to 511 bytes of kernel heap\ndata per TX frame.\n\nThe RX path does not have this problem: it allocates the skb with\nthe aligned length (alloc_len) before reading.\n\nCompute the exact padding with the bus align_size() callback, make\nsure queued TX frames have tailroom for it, and zero the padding\nbytes before the transfer so nothing past the frame is exposed.\n\nThis is not expected to change driver behavior on most cases: frame\ncontents and transfer sizes are unchanged, only the content of the\npadding bytes (previously undefined stale memory, now zero), which\nthe device never reads since the WSM header carries the real frame\nlength.  The skb expansion can only fail under memory exhaustion,\nin which case the frame is dropped like on the existing error paths\nof cw1200_tx().\n\nDiscovered by Atuin - Automated Vulnerability Discovery Engine.","summary":"The cw1200 Wi-Fi driver in the Linux kernel pads outgoing SDIO or SPI transfers past the end of the frame buffer, so up to 511 bytes of kernel heap memory per frame are sent to the wireless chip. The exposure is to the device itself, which a hostile or compromised wireless module could collect.","severity":"low","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["cw1200","embedded","linux-kernel","package","wifi"],"not_affected_if":["driver-not-loaded","no-cw1200-hardware"],"how_to_check":"- Check whether the cw1200 driver is loaded with `lsmod | grep cw1200` or whether `cw1200_wlan_sdio` or `cw1200_wlan_spi` modules exist for your kernel.\n- Compare the running kernel with the fixed release listed in the kernel stable tree commit for this CVE (unknown from the sources).","fix":"- Update the Linux kernel to a release that includes the upstream commit fixing cw1200 TX padding (exact fixed version: unknown from the sources).\n- If the cw1200 hardware is not used, blacklist the module, for example `echo 'blacklist cw1200_wlan_sdio' > /etc/modprobe.d/cw1200.conf`.","status":"open","published_at":"2026-10-18T16:17:24+00:00","first_seen_at":"2026-10-23T21:57:16+00:00","triaged_at":"2026-10-25T05:17:32+00:00","updated_at":"2026-10-25T05:17:32+00:00","category":"package","confidence":0.6,"triage":{"at":"2026-10-25T05:17:32Z","model":"claude-haiku-5-5","output":{"fix":"- Update the Linux kernel to a release that includes the upstream commit fixing cw1200 TX padding (exact fixed version: unknown from the sources).\n- If the cw1200 hardware is not used, blacklist the module, for example `echo 'blacklist cw1200_wlan_sdio' > /etc/modprobe.d/cw1200.conf`.","reach":"local","title":"Linux kernel: cw1200 Wi-Fi driver leaks heap bytes to its device","impact":"low","summary":"The cw1200 Wi-Fi driver in the Linux kernel pads outgoing SDIO or SPI transfers past the end of the frame buffer, so up to 511 bytes of kernel heap memory per frame are sent to the wireless chip. The exposure is to the device itself, which a hostile or compromised wireless module could collect.","category":"package","nicknames":[],"who_cares":["linux-kernel","embedded","wifi","cw1200"],"confidence":0.6,"needs_auth":"unknown","worst_case":"Up to 511 bytes of kernel heap data sent to the wireless chip per frame","analyst_note":"","how_to_check":"- Check whether the cw1200 driver is loaded with `lsmod | grep cw1200` or whether `cw1200_wlan_sdio` or `cw1200_wlan_spi` modules exist for your kernel.\n- Compare the running kernel with the fixed release listed in the kernel stable tree commit for this CVE (unknown from the sources).","needs_analyst":false,"not_affected_if":["no-cw1200-hardware","driver-not-loaded"],"who_is_affected":"Only systems running a kernel with the cw1200 Wi-Fi driver, which drives ST-Ericsson CW1200 wireless chips over SDIO or SPI, are exposed. The leak goes to the wireless chip, so the concern is mainly embedded boards or devices with this hardware, not general servers or desktops.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"low"},"cost_usd":0.000722,"input_tokens":3686,"output_tokens":707,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2026':15A,18A '-98711':16A,19A '1':125C '511':53B,121C,175C 'align':116C,117C,198C,211C 'alloc':193C,200C 'atuin':310C 'autom':311C 'behavior':245C 'bogus':169C 'buffer':49B,138C 'bus':115C,160C,210C 'byte':10A,54B,122C,126C,164C,176C,227C,262C 'callback':213C 'carri':162C,278C 'case':248C,294C 'chang':243C 'chip':66B 'collect':82B,172C 'compromis':78B 'comput':204C 'content':250C,258C 'could':81B 'cve':14A,17A 'cw1200':3A,20B,28B,94C,147C,306C 'data':102C,148C,180C 'devic':13A,72B,104C,167C,170C,271C 'discov':308C 'discoveri':313C 'driver':7A,32B,244C 'drop':298C 'embed':21B 'end':45B,154C 'engin':314C 'error':303C 'exact':206C 'exhaust':291C 'exist':302C 'expans':285C 'expect':241C 'expos':237C 'exposur':68B 'fail':288C 'fi':6A,31B 'fix':95C 'follow':88C 'frame':48B,60B,137C,157C,183C,218C,235C,249C,281C,296C 'header':277C 'heap':9A,57B,101C,179C 'hostil':76B 'kernel':2A,24B,36B,56B,86C,178C 'leak':8A,100C 'len':201C 'length':133C,199C,282C 'like':299C 'linux':1A,23B,35B,85C 'linux-kernel':22B 'make':214C 'memori':58B,266C,290C 'modul':80B 'never':272C 'noth':232C 'oob':98C 'outgo':38B 'packag':25B 'pad':37B,97C,132C,146C,207C,226C,261C 'past':43B,152C,233C 'path':107C,186C,304C 'per':59B,181C 'previous':263C 'problem':191C 'queu':216C 'read':99C,151C,203C,273C 'real':280C 'reserv':143C 'resolv':92C 'room':142C 'round':108C 'rx':185C 'sdio':39B,124C 'send':130C 'sent':62B 'sinc':274C 'size':111C,118C,212C,253C 'skb':195C,284C 'spi':41B,128C 'stale':265C 'straight':134C 'sure':215C 'tailroom':220C 'therefor':150C 'transfer':42B,110C,161C,230C,252C 'tx':96C,106C,182C,217C,307C 'unchang':255C 'undefin':264C 'vulner':89C,312C 'wi':5A,30B 'wi-fi':4A,29B 'wifi':26B,93C 'wireless':65B,79B 'write':149C 'wsm':276C 'zero':224C,268C","nicknames":[],"mitigations":[],"who_affected":"Only systems running a kernel with the cw1200 Wi-Fi driver, which drives ST-Ericsson CW1200 wireless chips over SDIO or SPI, are exposed. The leak goes to the wireless chip, so the concern is mainly embedded boards or devices with this hardware, not general servers or desktops.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-18T16:17:24+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-98711","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98711","severity":null,"published_at":"2026-10-18T16:17:24+00:00","modified_at":"2026-10-21T13:21:39+00:00","first_seen_at":"2026-10-23T21:57:16+00:00","fetched_at":"2026-10-23T22:28:56+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}