CVE-2026-98234— net/sched: hhf: cap hh_flows_limit at change time
Quick assessment
Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
在 Linux 内核中，已修复以下漏洞： net/sched: hhf：在变更时限制 hh_flows_limit 的上限 函数在存储 属性时未设置上限。过大的 会导致每个新的“重击”（heavy-hitter）流量都能通过 中的 检查，从而在遭受欺骗性流量攻击时，为每个流分配固定大小的 内存，引发无限制的内存增长。 通过将属性上限限制为 （即 中的默认值），并使用 进行策略约束，同时在拒绝非法值时通过 报告相关信息。保留已弃用的嵌套解析逻辑：由于传统的 tc（流量控制）在设置 时未设置 标志，因此必须兼容旧行为。
Possible ATT&CK Techniques 3 AI
T1496 · Resource Hijacking T1068 · Exploitation for Privilege Escalation T1548 · Abuse Elevation Control MechanismAffected Version Matrix 18
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Linux | Linux | 10239edf86f137ce4c39b62ea9575e8053c549a0< 7adfd0a42174b85c6bd678858ecd6674f403f336 |
affected |
10239edf86f137ce4c39b62ea9575e8053c549a0< 35fd423a5c5132c6f4321f6c4f0a7b4b90af830c |
affected | ||
10239edf86f137ce4c39b62ea9575e8053c549a0< 06d2a101e89063cb0b9b459104db48bdfb0a797d |
affected | ||
10239edf86f137ce4c39b62ea9575e8053c549a0< d8e2f1f0263b7c97b222c06070cccf13e0ab7112 |
affected | ||
10239edf86f137ce4c39b62ea9575e8053c549a0< f3f4a5cb4a6e9b1f1f25d34dfc25f836a1601db4 |
affected | ||
10239edf86f137ce4c39b62ea9575e8053c549a0< 1731ff1d20489afe4cd01b7d16d37f324746ac54 |
affected | ||
10239edf86f137ce4c39b62ea9575e8053c549a0< f6547d27ce2093c5627636fb63dd0b7523c466f9 |
affected | ||
10239edf86f137ce4c39b62ea9575e8053c549a0< 2cef2588c995722a901368def30befeef9ae55c6 |
affected | ||
| … +10 more rows | |||
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I. Basic Information for CVE-2026-98234
Vulnerability Information
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Vulnerability Title
net/sched: hhf: cap hh_flows_limit at change time
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Affected Products
II. Public POCs for CVE-2026-98234
| # | POC Description | Source Link | Shenlong Link |
|---|
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Patches & Fixes for CVE-2026-98234 (8)
Same Patch Batch · Linux · 2026-10-06 · 208 CVEs total
| CVE-2026-98323 | 9.8 CRITICAL | RDMA/siw: Bound fragmented header copies by the remaining length |
| CVE-2026-98365 | 9.8 CRITICAL | RDMA/rxe: Fix integer overflow in mr_check_range() leading to OOB access |
| CVE-2026-98282 | 8.8 HIGH | powerpc/iommu: Fix the overflow validation in iommu_tce_check_ioba |
| CVE-2026-98283 | 8.8 HIGH | KVM: PPC: Book3S HV: fix use-after-free in kvmhv_emulate_tlbie_all_lpid() |
| CVE-2026-98339 | 8.8 HIGH | wifi: cfg80211: don't filter by BSS type when removing stale entries |
| CVE-2026-98171 | 8.8 HIGH | smb: client: fix next_buffer UAF and NextCommand bounds in compound PDUs |
| CVE-2026-98261 | 8.1 HIGH | cifs: Fix server use-after-free in cifs_chan_skip_or_disable() |
| CVE-2026-98357 | 8.1 HIGH | IB/isert: wait for deferred control PDU completions before releasing the connection |
| CVE-2026-98239 | 8.1 HIGH | net: lan743x: fix RX checksum use-after-free |
| CVE-2026-98341 | 7.8 HIGH | wifi: cfg80211: don't free driver-owned scan requests |
| CVE-2026-98324 | 7.8 HIGH | dmaengine: pxa: fix double counting of the hw descriptors |
| CVE-2026-98320 | 7.8 HIGH | netfilter: flowtable: hold reference on ct until flow is released |
| CVE-2026-98228 | 7.8 HIGH | mips: select CONFIG_WEAK_REORDERING_BEYOND_LLSC from CONFIG_EYEQ |
| CVE-2026-98229 | 7.8 HIGH | xfrm: save input state data before secpath resets |
| CVE-2026-98318 | 7.8 HIGH | smb: client: validate absolute native symlink targets before NT fixups |
| CVE-2026-98315 | 7.8 HIGH | ntfs: protect runlist updates with the runlist lock |
| CVE-2026-98260 | 7.8 HIGH | exec: Cleanup POSIX timers right after de_thread() |
| CVE-2026-98256 | 7.8 HIGH | signal: Prevent exec() race |
| CVE-2026-98258 | 7.8 HIGH | posix-cpu-timers: Prevent freeing a timer which is queued on the expiry list |
| CVE-2026-98254 | 7.8 HIGH | swiotlb: use the adjusted address for the highmem page lookup |
Showing top 20 of 208 CVEs. View all on vendor page → →
IV. Related Vulnerabilities
Same product: Linux
-
CVE-2026-98384
bpf: Fix out-of-bounds read of sk_protocol in bpf_sock_destr -
CVE-2026-98383
bpf: Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL -
CVE-2026-98382
bpf: Reject dev-bound-only programs on other devices -
CVE-2026-98381
veth: manage XDP program pointers during channel resize -
CVE-2026-98380
net/sched: reject IDR error pointers when deleting actions
Same vendor: Linux
-
CVE-2026-98384
bpf: Fix out-of-bounds read of sk_protocol in bpf_sock_destr -
CVE-2026-98383
bpf: Disallow bpf_skb_pull_data() for LWT_SEG6LOCAL -
CVE-2026-98382
bpf: Reject dev-bound-only programs on other devices -
CVE-2026-98381
veth: manage XDP program pointers during channel resize -
CVE-2026-98380
net/sched: reject IDR error pointers when deleting actions
V. Comments for CVE-2026-98234
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