net/sched: sch_hfsc: bound the classify inner-filter walk with a drift budget
In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_hfsc: bound the classify inner-filter walk with a drift budget hfsc_classify() applies the "filter may only point downwards" level check only when the filter result carries no bound class. A filter created with a flowid gets res.class set once at bind time, so the check never runs for it during classification. hfsc_adjust_levels() can later raise a class's level without revalidating existing bindings, leaving two binds that were each legal at bind time pointing at each other; the classify walk then bounces between two interior classes forever with the qdisc lock held and BH disabled — a soft lockup from a single packet. The stuck walk trips the watchdog: watchdog: BUG: soft lockup - CPU#3 stuck for 13s! [ping:444] RIP: 0010:u32_classify+0x542/0x17f0 ... tcf_classify+0x66/0xa0 hfsc_enqueue+0x166/0xdf0 Bound the traversal with a budget of non-descending hops, the only way a configured walk can move without descending the class tree once levels drift after bind time. The budget is cumulative over the whole walk and is deliberately not reset on a descending hop: a chain that alternates a descent with a lateral hop would return the budget every lap and never trip. Descending hops never decrement it, so legitimately deep trees are unaffected and a terminating lateral chain still classifies normally. Drop the packet with a rate-limited warning once the budget is exhausted, mirroring the merged HTB fix
CVE-2026-98610
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-2026-98610
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": "a2f79227138c71e08627af5f8961197364edbc98",
"lessThan": "d4fd251e3311727c32af89344d3332f788c153a2",
"versionType": "git"
},
{
"status": "affected",
"version": "a2f79227138c71e08627af5f8961197364edbc98",
"lessThan": "30d7fea767e830bd81ac2f73d2e33c877cb2e679",
"versionType": "git"
},
{
"status": "affected",
"version": "a2f79227138c71e08627af5f8961197364edbc98",
"lessThan": "f476fb656ca2326d7b2eba98d03ced1cbcf5cd99",
"versionType": "git"
},
{
"status": "affected",
"version": "a2f79227138c71e08627af5f8961197364edbc98",
"lessThan": "e8f9979286f70dfbfe0552e2a63000950841bea6",
"versionType": "git"
},
{
"status": "affected",
"version": "a2f79227138c71e08627af5f8961197364edbc98",
"lessThan": "2bd20245dd658789d8cccb37697967b4caba6ad8",
"versionType": "git"
},
{
"status": "affected",
"version": "a2f79227138c71e08627af5f8961197364edbc98",
"lessThan": "0fa25ba50a382d79c0cf060214c2095756836f5f",
"versionType": "git"
},
{
"status": "affected",
"version": "a2f79227138c71e08627af5f8961197364edbc98",
"lessThan": "1301a1292c6742b4c96a18715d49f89c3caca0d7",
"versionType": "git"
},
{
"status": "affected",
"version": "a2f79227138c71e08627af5f8961197364edbc98",
"lessThan": "8a60ade2277e1f0e0d0578d565354e52292fa46d",
"versionType": "git"
}
],
"programFiles": [
"net/sched/sch_hfsc.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.35"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "2.6.35",
"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": "6.12.112",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.55",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.9",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/sched/sch_hfsc.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-98610
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #38629 · Revision 1
- Added to Heist Feed
- Publisher date