net/sched: sfq: clamp quantum in change path
In the Linux kernel, the following vulnerability has been resolved: net/sched: sfq: clamp quantum in change path sfq_change() accepts any non-negative quantum (only rejects (int)ctl->quantum < 0). With a crafted size table qdisc_pkt_len reaches ~2 GiB, so quantum=1 makes the deficit-refill loop spin ~2^31 times under the qdisc lock (a soft lockup / denial of service). Add max(256U, ...) matching fq_codel_change(). Reject quantum > 1<<20 with -EINVAL, matching fq_codel_change() and the init clamp. Conditions to recreate the bug: CONFIG_NET_SCH_SFQ=y. Requires CAP_NET_ADMIN (namespace-local via unshare -Urn suffices). tc qdisc add dev dummy0 root sfq tc qdisc change dev dummy0 root sfq quantum 1 stab data 32768 size_log 15 cell_log 0
CVE-2026-98012
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-2026-98012
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": "4919649699c5f4dbae08b8e2ed536fc9d6c3c2aa",
"lessThan": "4117c528b2de5fdc3e4a7e3626815b616a635cdc",
"versionType": "git"
},
{
"status": "affected",
"version": "548cf048b426729a7a1fa6acd1271c010c9a7380",
"lessThan": "f82fa6f10d4a69322cad0f7a4aa523ce6292a5a0",
"versionType": "git"
},
{
"status": "affected",
"version": "c49ac48fac51a6a54efd5963954d02bacf075085",
"lessThan": "0692ce5a528df450d64e9f819054177e9d91076f",
"versionType": "git"
},
{
"status": "affected",
"version": "58ae7465f0e7113d45aa88a66bf2d203c71c195e",
"lessThan": "e4192bcf83aaab02129644ddf4656fd86e93751f",
"versionType": "git"
},
{
"status": "affected",
"version": "82bd38bd5467ece1ee274b493f51326cf5220a5a",
"lessThan": "f3820dce042a673fcb28cc31c87ee14257e21a17",
"versionType": "git"
},
{
"status": "affected",
"version": "e4650d7ae4252f67e997a632adfae0dd74d3a99a",
"lessThan": "534cd7ecbbc6e8a974f4003a5c1557439c6e0a72",
"versionType": "git"
},
{
"status": "affected",
"version": "e4650d7ae4252f67e997a632adfae0dd74d3a99a",
"lessThan": "e6c1cb728e389354203a72bc77464c222a247aeb",
"versionType": "git"
},
{
"status": "affected",
"version": "e4650d7ae4252f67e997a632adfae0dd74d3a99a",
"lessThan": "fb9f88a33c516ea5c0bcd9a22ca288b246b34567",
"versionType": "git"
},
{
"status": "affected",
"version": "843cacb88f42f426973f1ed11c6fb562558efb27",
"versionType": "git"
},
{
"status": "affected",
"version": "5.10.239",
"lessThan": "5.10.271",
"versionType": "semver"
},
{
"status": "affected",
"version": "5.15.186",
"lessThan": "5.15.222",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.1.129",
"lessThan": "6.1.189",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.6.76",
"lessThan": "6.6.158",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.12.13",
"lessThan": "6.12.111",
"versionType": "semver"
},
{
"status": "affected",
"version": "5.4.297",
"lessThan": "5.5",
"versionType": "semver"
}
],
"programFiles": [
"net/sched/sch_sfq.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.13"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.13",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.271",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.222",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.189",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.158",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.111",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.53",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.7",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/sched/sch_sfq.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-98012
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #38139 · Revision 1
- Added to Heist Feed
- Publisher date