xhci: fix lost bounce buffers on TDs spanning several ring segments
In the Linux kernel, the following vulnerability has been resolved: xhci: fix lost bounce buffers on TDs spanning several ring segments When a TD reaches a link TRB with data that is not aligned to the endpoint's wMaxPacketSize, xhci_align_td() stages the unalignable tail through the bounce buffer of the ring segment holding that link TRB. xhci_unmap_td_bounce_buffer() later unmaps it and, for IN transfers, copies the data back into the URB's buffer. The enqueue path records the segment that was bounced in td->bounce_seg, under the assumption that a TD never spans more than two ring segments. That assumption does not hold: a TD large enough to span three or more segments crosses several link TRBs and can be bounced at each of them. Only the last one survives in td->bounce_seg, so every earlier bounce buffer is neither copied back nor DMA unmapped. The URB still completes with actual_length equal to the requested length and no error, so the transfer looks successful while a wMaxPacketSize sized hole in the destination buffer silently keeps its previous contents. It also leaks a DMA mapping per dropped bounce. Any sufficiently large and fragmented bulk transfer can hit this. It was found with a USB mass storage device behind xHCI backing a dm-verity target with 512 byte hash blocks, where the stale data is detected rather than silently consumed. The device enumerates as SuperSpeed, so wMaxPacketSize is 1024, while dm-bufio issues one 512 byte bio per hash block. verity_prefetch
CVE-2026-90015
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-90015
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "f9c589e142d04b8a19eb382162f804d17102b5ed",
"lessThan": "c8124b28f12dbdd126118e63d0ebf8093a01fb81",
"versionType": "git"
},
{
"status": "affected",
"version": "f9c589e142d04b8a19eb382162f804d17102b5ed",
"lessThan": "e04d5304a248e5d2a7f4faa87541644bdd320cfb",
"versionType": "git"
},
{
"status": "affected",
"version": "f9c589e142d04b8a19eb382162f804d17102b5ed",
"lessThan": "a1629dfb011446d02905778f6df19f14c5f4f3b3",
"versionType": "git"
},
{
"status": "affected",
"version": "f9c589e142d04b8a19eb382162f804d17102b5ed",
"lessThan": "43239fc6dfb62c50ae1b9c0e82bac0f8cd2e285c",
"versionType": "git"
},
{
"status": "affected",
"version": "f9c589e142d04b8a19eb382162f804d17102b5ed",
"lessThan": "3c9a2b5a4f1183696f02ac280ced1d34afb409b1",
"versionType": "git"
},
{
"status": "affected",
"version": "f9c589e142d04b8a19eb382162f804d17102b5ed",
"lessThan": "efaab8938fb92979be6df359f7d1a43fb7e4717d",
"versionType": "git"
},
{
"status": "affected",
"version": "f9c589e142d04b8a19eb382162f804d17102b5ed",
"lessThan": "7236bbd2cb7d9fc0eda896bbd34790341e2a4377",
"versionType": "git"
},
{
"status": "affected",
"version": "f9c589e142d04b8a19eb382162f804d17102b5ed",
"lessThan": "ff44dfb03a293bf30e31f98772a1dd316a6071d1",
"versionType": "git"
}
],
"programFiles": [
"drivers/usb/host/xhci-ring.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.8"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.8",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.270",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.221",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.188",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.157",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.110",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.51",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.5",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/usb/host/xhci-ring.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-90015
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #36448 · Revision 1
- Added to Heist Feed
- Publisher date