net/sched: hhf: cap hh_flows_limit at change time
In the Linux kernel, the following vulnerability has been resolved: net/sched: hhf: cap hh_flows_limit at change time hhf_change() stores TCA_HHF_HH_FLOWS_LIMIT with no upper bound. A huge hh_flows_limit lets each new heavy-hitter flow pass the hh_flows_current_cnt check in alloc_new_hh() and forces a fixed-size kzalloc(GFP_ATOMIC) per flow under spoofed traffic, for unbounded memory growth. Bound the attribute with NLA_POLICY_MAX() at 2*HH_FLOWS_CNT (the hhf_init() default) and report the rejected value via extack. The deprecated nested parse is kept: legacy tc does not set NLA_F_NESTED on TCA_OPTIONS. Configs relying on hh_limit above the default were relying on unbounded, unsafe behaviour and are not supported going forward. hhf_init() also ran hhf_change() before setting the default hh_flows_limit, so a user-supplied hh_limit at add time was clobbered back to 2048. Set the default before hhf_change() so the configured value sticks. This is a follow-up to commit eb56a495f59b ("net/sched: hhf: clamp quantum in change and init paths"), which bounded the quantum of the same qdisc; the hh_flows_limit bound is the remaining unbounded knob of that series' scope. Conditions to recreate the bug: CAP_NET_ADMIN in a user namespace; tc qdisc change dev X root hhf hh_limit 4294967295 succeeds and the value is echoed by tc qdisc show, unbounding heavy-hitter flow allocations; also tc qdisc add dev X root hhf hh_limit 500 stores 2048 instead of 500.
CVE-2026-98234
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-2026-98234
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": "10239edf86f137ce4c39b62ea9575e8053c549a0",
"lessThan": "7adfd0a42174b85c6bd678858ecd6674f403f336",
"versionType": "git"
},
{
"status": "affected",
"version": "10239edf86f137ce4c39b62ea9575e8053c549a0",
"lessThan": "35fd423a5c5132c6f4321f6c4f0a7b4b90af830c",
"versionType": "git"
},
{
"status": "affected",
"version": "10239edf86f137ce4c39b62ea9575e8053c549a0",
"lessThan": "06d2a101e89063cb0b9b459104db48bdfb0a797d",
"versionType": "git"
},
{
"status": "affected",
"version": "10239edf86f137ce4c39b62ea9575e8053c549a0",
"lessThan": "d8e2f1f0263b7c97b222c06070cccf13e0ab7112",
"versionType": "git"
},
{
"status": "affected",
"version": "10239edf86f137ce4c39b62ea9575e8053c549a0",
"lessThan": "f3f4a5cb4a6e9b1f1f25d34dfc25f836a1601db4",
"versionType": "git"
},
{
"status": "affected",
"version": "10239edf86f137ce4c39b62ea9575e8053c549a0",
"lessThan": "1731ff1d20489afe4cd01b7d16d37f324746ac54",
"versionType": "git"
},
{
"status": "affected",
"version": "10239edf86f137ce4c39b62ea9575e8053c549a0",
"lessThan": "f6547d27ce2093c5627636fb63dd0b7523c466f9",
"versionType": "git"
},
{
"status": "affected",
"version": "10239edf86f137ce4c39b62ea9575e8053c549a0",
"lessThan": "2cef2588c995722a901368def30befeef9ae55c6",
"versionType": "git"
}
],
"programFiles": [
"net/sched/sch_hhf.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "3.14"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "3.14",
"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": "6.18.54",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.8",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/sched/sch_hhf.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-98234
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #38314 · Revision 1
- Added to Heist Feed
- Publisher date