{"id":"CVE-2026-98827","summary":"wifi: ath9k_htc: bound TX aggregation to MAX_TX_BUF_SIZE","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nwifi: ath9k_htc: bound TX aggregation to MAX_TX_BUF_SIZE\n\n__hif_usb_tx() dequeues up to MAX_TX_AGGR_NUM (20) frames into a\nsingle tx_buf of MAX_TX_BUF_SIZE (32768) bytes, limiting the batch\nby record count but never by cumulative byte length.\n\nWith large frames (MTU 2304), 20 aggregated frames of 2292 bytes\neach exceed the allocation (20 * 2296 = 45920 bytes), so the\nmemcpy() in the loop writes up to 13152 bytes past tx_buf-\u003ebuf\nbefore usb_submit_urb().\n\nPeek the queue head and stop before copying any record that would\ncross MAX_TX_BUF_SIZE, then dispatch the current batch. Leftover\nskbs remain queued and are drained on the next URB completion.\n\nThe byte bound changes the loop's exit semantics: it can now exit\nbefore i == tx_skb_cnt - 1. Stock only finalized tx_buf-\u003elen on\nthat last index (len += offset), so an early break would submit a\nURB holding only the last record's length while every dequeued skb\nis freed on completion, silently dropping frames. Make tx_buf-\u003elen\na running total and advance tx_buf-\u003eoffset per record instead; the\nstride round_up(nskb-\u003elen + 4, 4) is identical to the stock stride\nwhen the loop runs to completion.\n\nTested on hardware with an MTU 2304 flood: the loop stops at\nrecord 15 (len = 32144, offset = 32144, within 32768), no\noversized URB is submitted, and MTU 1500 pings pass 20/20.","modified":"2026-10-19T02:46:05.814412638Z","published":"2026-10-18T15:49:20.872Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98827.json"},"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/345ce265cf604e84b5b560c21beaf4c6f269ab14"},{"type":"WEB","url":"https://git.kernel.org/stable/c/aeaca27c1db3106967ffbb2b517d98c835f6d500"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c18882768a0fe253c70986c5fe66d9241570fbc4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e73a619f91b6cfec47bc1a94aea28df6849e5be3"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98827.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98827"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"fb9987d0f748c983bb795a86f47522313f701a08"},{"fixed":"c18882768a0fe253c70986c5fe66d9241570fbc4"},{"fixed":"345ce265cf604e84b5b560c21beaf4c6f269ab14"},{"fixed":"e73a619f91b6cfec47bc1a94aea28df6849e5be3"},{"fixed":"aeaca27c1db3106967ffbb2b517d98c835f6d500"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98827.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.35"},{"fixed":"6.12.113"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.56"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.10"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98827.json"}}],"schema_version":"1.9.0"}