CVE-2026-98827
In the Linux kernel, the following vulnerability has been resolved:
wifi: ath9k_htc: bound TX aggregation to MAX_TX_BUF_SIZE
__hif_usb_tx() dequeues up to MAX_TX_AGGR_NUM (20) frames into a single tx_buf of MAX_TX_BUF_SIZE (32768) bytes, limiting the batch by record count but never by cumulative byte length.
With large frames (MTU 2304), 20 aggregated frames of 2292 bytes each exceed the allocation (20 * 2296 = 45920 bytes), so the memcpy() in the loop writes up to 13152 bytes past tx_buf->buf before usb_submit_urb().
Peek the queue head and stop before copying any record that would cross MAX_TX_BUF_SIZE, then dispatch the current batch. Leftover skbs remain queued and are drained on the next URB completion.
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The byte bound changes the loop's exit semantics: it can now exit before i == tx_skb_cnt - 1. Stock only finalized tx_buf->len on that last index (len += offset), so an early break would submit a URB holding only the last record's length while every dequeued skb is freed on completion, silently dropping frames. Make tx_buf->len a running total and advance tx_buf->offset per record instead; the stride round_up(nskb->len + 4, 4) is identical to the stock stride when the loop runs to completion.
Tested on hardware with an MTU 2304 flood: the loop stops at record 15 (len = 32144, offset = 32144, within 32768), no oversized URB is submitted, and MTU 1500 pings pass 20/20.
CVSS
NVD hasn't assigned a CVSS score to this CVE (common since the April 2026 policy change).
Exploitation probability (EPSS)
- Probability of exploitation in the next 30 days
- 0.20 %
- Percentile among all scored CVEs
- 9
- Score date
- 10/20/2026
EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).
Affected technologies (1)
⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.
References
Show 4 references
Raw JSON (NVD)
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{
"id": "CVE-2026-98827",
"cveTags": [],
"metrics": {},
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "fb9987d0f748c983bb795a86f47522313f701a08",
"lessThan": "c18882768a0fe253c70986c5fe66d9241570fbc4",
"versionType": "git"
},
{
"status": "affected",
"version": "fb9987d0f748c983bb795a86f47522313f701a08",
"lessThan": "345ce265cf604e84b5b560c21beaf4c6f269ab14",
"versionType": "git"
},
{
"status": "affected",
"version": "fb9987d0f748c983bb795a86f47522313f701a08",
"lessThan": "e73a619f91b6cfec47bc1a94aea28df6849e5be3",
"versionType": "git"
},
{
"status": "affected",
"version": "fb9987d0f748c983bb795a86f47522313f701a08",
"lessThan": "aeaca27c1db3106967ffbb2b517d98c835f6d500",
"versionType": "git"
}
],
"programFiles": [
"drivers/net/wireless/ath/ath9k/hif_usb.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.35"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "2.6.35",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.12.113",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.56",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.10",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/net/wireless/ath/ath9k/hif_usb.c"
],
"defaultStatus": "affected"
}
]
}
],
"published": "2026-10-18T16:17:36.937",
"references": [
{
"url": "https://git.kernel.org/stable/c/345ce265cf604e84b5b560c21beaf4c6f269ab14",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/aeaca27c1db3106967ffbb2b517d98c835f6d500",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/c18882768a0fe253c70986c5fe66d9241570fbc4",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/e73a619f91b6cfec47bc1a94aea28df6849e5be3",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "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->buf\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->len 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->len\na running total and advance tx_buf->offset per record instead; the\nstride round_up(nskb->len + 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."
}
],
"lastModified": "2026-10-19T10:19:46.750",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}