CVE-2026-74560 (GCVE-0-2026-74560)
Vulnerability from cvelistv5
Published
2026-08-15 12:28
Modified
2026-08-17 05:21
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
xsk: fix buffer leak in xsk_drop_skb() for AF_XDP multi-buffer Tx
This patch is inspired by the check[1] from sashiko. It says when
overflow happens, the address of cq to be published is invalid.
Actually the severer thing is the whole process of publishing the
address of cq in this particular case is not right: it should truely
publish the address and advance the cached_prod in cq as long as it
reads descriptors from txq.
The following is the full analysis.
xsk_drop_skb() is called in three places, which all discard a partially
built multi-buffer skb:
1) xsk_build_skb() -EOVERFLOW error path: packet exceeds MAX_SKB_FRAGS
2) __xsk_generic_xmit() post-loop cleanup: an invalid descriptor in
the TX ring prevents the partial packet from completing
3) xsk_release(): socket close while xs->skb holds an incomplete packet
In all three cases, the TX descriptors for the already-processed frags
have been consumed from the TX ring (xskq_cons_release), and CQ slots
have been reserved. However, xsk_drop_skb() calls xsk_consume_skb()
which cancels the CQ reservations via xsk_cq_cancel_locked(). Since
the buffer addresses never appear in the completion queue, userspace
permanently loses track of these buffers.
Fix this by letting consume_skb() trigger the existing xsk_destruct_skb
destructor, which already submits buffer addresses to the CQ via
xsk_cq_submit_addr_locked().
Note that cancelling the descriptors back to the TX ring (via
xskq_cons_cancel_n) is not a appropriate option because an oversized
packet that always exceeds MAX_SKB_FRAGS would be retried indefinitely,
which is an obviously deadlock bug in the TX path.
Also move the desc->addr assignment in xsk_build_skb() above the
overflow check so that the current descriptor's address is recorded
before a potential -EOVERFLOW jump to free_err, consistent with the
zerocopy path in xsk_build_skb_zerocopy().
[1]: https://lore.kernel.org/all/20260425041726.85FB3C2BCB2@smtp.kernel.org/
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/xdp/xsk.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "05e283466b86e0b25a5209a3eafe87aa9886064a",
"status": "affected",
"version": "cf24f5a5feeaae34c1a34d1e04f8ac697290427a",
"versionType": "git"
},
{
"lessThan": "a0528ab6af62bf57153caaf8ea28e5fcb0e18fd4",
"status": "affected",
"version": "cf24f5a5feeaae34c1a34d1e04f8ac697290427a",
"versionType": "git"
},
{
"lessThan": "a3c8382ebce4780c6b3ace2c09bc342313ac0186",
"status": "affected",
"version": "cf24f5a5feeaae34c1a34d1e04f8ac697290427a",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/xdp/xsk.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.6"
},
{
"lessThan": "6.6",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.44",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.8",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.44",
"versionStartIncluding": "6.6",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.8",
"versionStartIncluding": "6.6",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "6.6",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxsk: fix buffer leak in xsk_drop_skb() for AF_XDP multi-buffer Tx\n\nThis patch is inspired by the check[1] from sashiko. It says when\noverflow happens, the address of cq to be published is invalid.\nActually the severer thing is the whole process of publishing the\naddress of cq in this particular case is not right: it should truely\npublish the address and advance the cached_prod in cq as long as it\nreads descriptors from txq.\n\nThe following is the full analysis.\nxsk_drop_skb() is called in three places, which all discard a partially\nbuilt multi-buffer skb:\n1) xsk_build_skb() -EOVERFLOW error path: packet exceeds MAX_SKB_FRAGS\n2) __xsk_generic_xmit() post-loop cleanup: an invalid descriptor in\n the TX ring prevents the partial packet from completing\n3) xsk_release(): socket close while xs-\u003eskb holds an incomplete packet\n\nIn all three cases, the TX descriptors for the already-processed frags\nhave been consumed from the TX ring (xskq_cons_release), and CQ slots\nhave been reserved. However, xsk_drop_skb() calls xsk_consume_skb()\nwhich cancels the CQ reservations via xsk_cq_cancel_locked(). Since\nthe buffer addresses never appear in the completion queue, userspace\npermanently loses track of these buffers.\n\nFix this by letting consume_skb() trigger the existing xsk_destruct_skb\ndestructor, which already submits buffer addresses to the CQ via\nxsk_cq_submit_addr_locked().\n\nNote that cancelling the descriptors back to the TX ring (via\nxskq_cons_cancel_n) is not a appropriate option because an oversized\npacket that always exceeds MAX_SKB_FRAGS would be retried indefinitely,\nwhich is an obviously deadlock bug in the TX path.\n\nAlso move the desc-\u003eaddr assignment in xsk_build_skb() above the\noverflow check so that the current descriptor\u0027s address is recorded\nbefore a potential -EOVERFLOW jump to free_err, consistent with the\nzerocopy path in xsk_build_skb_zerocopy().\n\n[1]: https://lore.kernel.org/all/20260425041726.85FB3C2BCB2@smtp.kernel.org/"
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:21:47.344Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/05e283466b86e0b25a5209a3eafe87aa9886064a"
},
{
"url": "https://git.kernel.org/stable/c/a0528ab6af62bf57153caaf8ea28e5fcb0e18fd4"
},
{
"url": "https://git.kernel.org/stable/c/a3c8382ebce4780c6b3ace2c09bc342313ac0186"
}
],
"title": "xsk: fix buffer leak in xsk_drop_skb() for AF_XDP multi-buffer Tx",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-74560",
"datePublished": "2026-08-15T12:28:03.912Z",
"dateReserved": "2026-08-15T05:44:03.916Z",
"dateUpdated": "2026-08-17T05:21:47.344Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
Loading…
Loading…
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
Loading…
Loading…