net/sched: cls_u32: skip hash tables in u32_bind_class()
In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_u32: skip hash tables in u32_bind_class() u32_walk() enumerates both struct tc_u_hnode and struct tc_u_knode through the walker callback. u32_bind_class() unconditionally casts the passed fh to tc_u_knode and accesses &n->res, so when fh is actually a tc_u_hnode, which has no tcf_result member, this results in a slab-out-of-bounds read of res->classid in tc_cls_bind_class(). The issue can be reproduced with the following commands: tc qdisc add dev lo root handle 1: hfsc tc class add dev lo parent 1: classid 1:1 hfsc sc rate 1000kbit tc filter add dev lo parent 1:1 protocol ip prio 1 u32 match u32 0 0 flowid 1:1 tc class add dev lo parent 1: classid 1:2 hfsc sc rate 2000kbit Fix this by skipping hash tables via the TC_U32_KEY(handle) check.
CVE-2026-74739
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-2026-74739
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": "07d79fc7d94e3f884b8b1c95aa615b202bb5e4c1",
"lessThan": "ec5f3005586a785689fd568361b0c5925cb1548b",
"versionType": "git"
},
{
"status": "affected",
"version": "07d79fc7d94e3f884b8b1c95aa615b202bb5e4c1",
"lessThan": "19d114b93c94bdef70496f26685c2a6b242f41b3",
"versionType": "git"
},
{
"status": "affected",
"version": "07d79fc7d94e3f884b8b1c95aa615b202bb5e4c1",
"lessThan": "594a064d603202b9ee21e07679d854e5c1750cc4",
"versionType": "git"
},
{
"status": "affected",
"version": "07d79fc7d94e3f884b8b1c95aa615b202bb5e4c1",
"lessThan": "31f26a95eeee926946809ac456c61a3217936a62",
"versionType": "git"
},
{
"status": "affected",
"version": "07d79fc7d94e3f884b8b1c95aa615b202bb5e4c1",
"lessThan": "e71f8e9ed6f311410b14741f6012afe01869c0fa",
"versionType": "git"
},
{
"status": "affected",
"version": "07d79fc7d94e3f884b8b1c95aa615b202bb5e4c1",
"lessThan": "6d3724e616faf952c3adcf8414fc21a828ef3709",
"versionType": "git"
}
],
"programFiles": [
"net/sched/cls_u32.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.14"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.14",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.1.184",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.153",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.105",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.46",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.10",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/sched/cls_u32.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-74739
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #34290 · Revision 1
- Added to Heist Feed
- Publisher date