net/sched: sfq: clamp quantum in change path
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
- —
- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 5 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
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
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 5.10.239 to before 5.10.271; 5.15.186 to before 5.15.222; 6.1.129 to before 6.1.189; 6.6.76 to before 6.6.158; 6.12.13 to before 6.12.111; 5.4.297 to before 5.5 | 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, 5.5 | Patch available | CNA |
| Linux | Linux | 6.13 and later | 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, 6.18.53, 7.2.7, 7.3 | Patch available | CNA |
- Linux VendorLinux Affected 5.10.239 to before 5.10.271; 5.15.186 to before 5.15.222; 6.1.129 to before 6.1.189; 6.6.76 to before 6.6.158; 6.12.13 to before 6.12.111; 5.4.297 to before 5.5 Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, 5.5 Patch available CNA
- Linux VendorLinux Affected 6.13 and later Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, 6.18.53, 7.2.7, 7.3 Patch available CNA
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, 5.5
- Fix · CNA Linux (Linux) Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, 6.18.53, 7.2.7, 7.3
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 4 products
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4
Timeline
- 2026-10-02 Threatist record created from CVE-2026-98012
- 2026-10-03 Alias added: GHSA-wq2r-f96j-67j9
- 2026-10-03 Fix available: Linux/Linux@0692ce5a528df450d64e9f819054177e9d91076f, Linux/Linux@4117c528b2de5fdc3e4a7e3626815b616a635cdc, Linux/[email protected] +5 · CNA
- 2026-10-03 4 new references · CNA
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-11-07 Affected versions changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/4117c528b2de5fdc3e4a7e3626815b616a635cdc
- https://git.kernel.org/stable/c/f82fa6f10d4a69322cad0f7a4aa523ce6292a5a0
- https://git.kernel.org/stable/c/0692ce5a528df450d64e9f819054177e9d91076f
- https://git.kernel.org/stable/c/e4192bcf83aaab02129644ddf4656fd86e93751f
- https://git.kernel.org/stable/c/f3820dce042a673fcb28cc31c87ee14257e21a17
- https://git.kernel.org/stable/c/534cd7ecbbc6e8a974f4003a5c1557439c6e0a72
- https://git.kernel.org/stable/c/e6c1cb728e389354203a72bc77464c222a247aeb
- https://git.kernel.org/stable/c/fb9f88a33c516ea5c0bcd9a22ca288b246b34567
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Sources
- CVE-2026-98012 · CVE Program
- CVE-2026-98012 · NVD
- FIRST EPSS
- GHSA-wq2r-f96j-67j9 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98012 · Red Hat security data · CC BY 4.0
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