net/sched: Always pass notifications when child class becomes empty
In the Linux kernel, the following vulnerability has been resolved: net/sched: Always pass notifications when child class becomes empty Certain classful qdiscs may invoke their classes' dequeue handler on an enqueue operation. This may unexpectedly empty the child qdisc and thus make an in-flight class passive via qlen_notify(). Most qdiscs do not expect such behaviour at this point in time and may re-activate the class eventually anyways which will lead to a use-after-free. The referenced fix commit attempted to fix this behavior for the HFSC case by moving the backlog accounting around, though this turned out to be incomplete since the parent's parent may run into the issue too. The following reproducer demonstrates this use-after-free: tc qdisc add dev lo root handle 1: drr tc filter add dev lo parent 1: basic classid 1:1 tc class add dev lo parent 1: classid 1:1 drr tc qdisc add dev lo parent 1:1 handle 2: hfsc def 1 tc class add dev lo parent 2: classid 2:1 hfsc rt m1 8 d 1 m2 0 tc qdisc add dev lo parent 2:1 handle 3: netem tc qdisc add dev lo parent 3:1 handle 4: blackhole echo 1 | socat -u STDIN UDP4-DATAGRAM:127.0.0.1:8888 tc class delete dev lo classid 1:1 echo 1 | socat -u STDIN UDP4-DATAGRAM:127.0.0.1:8888 Since backlog accounting issues leading to a use-after-frees on stale class pointers is a recurring pattern at this point, this patch takes a different approach. Instead of trying to fix the accounting, the patch ensures that qdisc_tree_reduce_backlog always cal
CVE-2025-38350
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-2025-38350
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": "1034e3310752e8675e313f7271b348914008719a",
"lessThan": "3b290923ad2b23596208c1e29520badef4356a43",
"versionType": "git"
},
{
"status": "affected",
"version": "f9f593e34d2fb67644372c8f7b033bdc622ad228",
"lessThan": "e9921b57dca05ac5f4fa1fa8e993d4f0ee52e2b7",
"versionType": "git"
},
{
"status": "affected",
"version": "89c301e929a0db14ebd94b4d97764ce1d6981653",
"lessThan": "e269f29e9395527bc00c213c6b15da04ebb35070",
"versionType": "git"
},
{
"status": "affected",
"version": "f1dde3eb17dc1b8bd07aed00004b1e05fc87a3d4",
"lessThan": "7874c9c132e906a52a187d045995b115973c93fb",
"versionType": "git"
},
{
"status": "affected",
"version": "93c276942e75de0e5bc91576300d292e968f5a02",
"lessThan": "f680a4643c6f71e758d8fe0431a958e9a6a4f59d",
"versionType": "git"
},
{
"status": "affected",
"version": "49b21795b8e5654a7df3d910a12e1060da4c04cf",
"lessThan": "a553afd91f55ff39b1e8a1c4989a29394c9e0472",
"versionType": "git"
},
{
"status": "affected",
"version": "3f981138109f63232a5fb7165938d4c945cc1b9d",
"lessThan": "a44acdd9e84a211989ff4b9b92bf3545d8456ad5",
"versionType": "git"
},
{
"status": "affected",
"version": "3f981138109f63232a5fb7165938d4c945cc1b9d",
"lessThan": "103406b38c600fec1fe375a77b27d87e314aea09",
"versionType": "git"
},
{
"status": "affected",
"version": "3f3a22eebbc32b4fa8ce9c1d5f9db214b45b9335",
"versionType": "git"
},
{
"status": "affected",
"version": "5.4.294",
"lessThan": "5.4.296",
"versionType": "semver"
},
{
"status": "affected",
"version": "5.10.238",
"lessThan": "5.10.240",
"versionType": "semver"
},
{
"status": "affected",
"version": "5.15.185",
"lessThan": "5.15.187",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.1.141",
"lessThan": "6.1.144",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.6.93",
"lessThan": "6.6.97",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.12.31",
"lessThan": "6.12.37",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.14.9",
"lessThan": "6.15",
"versionType": "semver"
}
],
"programFiles": [
"net/sched/sch_api.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.15"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.15",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.4.296",
"versionType": "semver",
"lessThanOrEqual": "5.4.*"
},
{
"status": "unaffected",
"version": "5.10.240",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.187",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.144",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.97",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.37",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.15.6",
"versionType": "semver",
"lessThanOrEqual": "6.15.*"
},
{
"status": "unaffected",
"version": "6.16",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/sched/sch_api.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2025-38350
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #27030 · Revision 1
- Added to Heist Feed
- Publisher date