ghsa-vwv2-fc39-c5f6
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
net/sched: sch_cake: Fix incorrect qlen reduction in cake_drop
In cake_drop(), qdisc_tree_reduce_backlog() is used to update the qlen and backlog of the qdisc hierarchy. Its caller, cake_enqueue(), assumes that the parent qdisc will enqueue the current packet. However, this assumption breaks when cake_enqueue() returns NET_XMIT_CN: the parent qdisc stops enqueuing current packet, leaving the tree qlen/backlog accounting inconsistent. This mismatch can lead to a NULL dereference (e.g., when the parent Qdisc is qfq_qdisc).
This patch computes the qlen/backlog delta in a more robust way by observing the difference before and after the series of cake_drop() calls, and then compensates the qdisc tree accounting if cake_enqueue() returns NET_XMIT_CN.
To ensure correct compensation when ACK thinning is enabled, a new variable is introduced to keep qlen unchanged.
{
"affected": [],
"aliases": [
"CVE-2025-68325"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-12-18T15:16:06Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_cake: Fix incorrect qlen reduction in cake_drop\n\nIn cake_drop(), qdisc_tree_reduce_backlog() is used to update the qlen\nand backlog of the qdisc hierarchy. Its caller, cake_enqueue(), assumes\nthat the parent qdisc will enqueue the current packet. However, this\nassumption breaks when cake_enqueue() returns NET_XMIT_CN: the parent\nqdisc stops enqueuing current packet, leaving the tree qlen/backlog\naccounting inconsistent. This mismatch can lead to a NULL dereference\n(e.g., when the parent Qdisc is qfq_qdisc).\n\nThis patch computes the qlen/backlog delta in a more robust way by\nobserving the difference before and after the series of cake_drop()\ncalls, and then compensates the qdisc tree accounting if cake_enqueue()\nreturns NET_XMIT_CN.\n\nTo ensure correct compensation when ACK thinning is enabled, a new\nvariable is introduced to keep qlen unchanged.",
"id": "GHSA-vwv2-fc39-c5f6",
"modified": "2025-12-18T15:30:45Z",
"published": "2025-12-18T15:30:45Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-68325"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0b6216f9b3d1c33c76f74511026e5de5385ee520"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3ed6c458530a547ed0c9ea0b02b19bab620be88b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/529c284cc2815c8350860e9a31722050fe7117cb"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9fefc78f7f02d71810776fdeb119a05a946a27cc"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
| Author | Source | Type | Date |
|---|
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- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.