Medium 5.5Published Apr 13, 2026

CVE-2026-31423net/sched: sch_hfsc: fix divide-by-zero in rtsc_min()

Updated under an hour ago (Oct 27, 2026, 3:10 PM ET)

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It affects Linux and 4 other products. Add what you run to find out whether that includes you.

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Exploited in the last 30 days

In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_hfsc: fix divide-by-zero in rtsc_min() m2sm() converts a u32 slope to a u64 scaled value. For large inputs (e.g. m1=4000000000), the result can reach 2^32. rtsc_min() stores the difference of two such u64 values in a u32 variable `dsm` and uses it as a divisor. When the difference is exactly 2^32 the truncation yields zero, causing a divide-by-zero oops in the concave-curve intersection path: Oops: divide error: 0000 RIP: 0010:rtsc_min (net/sched/sch_hfsc.c:601) Call Trace: init_ed (net/sched/sch_hfsc.c:629) hfsc_enqueue (net/sched/sch_hfsc.c:1569) [...] Widen `dsm` to u64 and replace do_div() with div64_u64() so the full difference is preserved.

CVSS: 5.5 MEDIUM (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 14, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before ad8e8fec40290a8c8cf145c0deaadf76f80c5163; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before ab1ff5890c7354afc7be56502fcfbd61f3b7ae4f; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 25b6821884713a31e2b49fb67b0ebd765b33e0a9; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before c56f78614e7781aaceca9bd3cb2128bf7d45c3bd; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before b9e6431cbea8bb1fae8069ed099b4ee100499835; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 17c1b9807b8a67d676b6dcf749ee932ebaa7f568; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before d0aefec1b1a1ba2c1d251028dc2c4e5b4ce1fea5; from 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 before 4576100b8cd03118267513cafacde164b498b322	CNA record
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
linux linux_kernel linux:linux_kernel	from 2.6.12.1 before 5.10.253; from 5.11 before 5.15.203; from 5.16 before 6.1.168; from 6.2 before 6.6.134; from 6.7 before 6.12.81; from 6.13 before 6.18.22; from 6.19 before 6.19.12; 2.6.12; and 10 more ranges	NVD

References

References

https://git.kernel.org/stable/c/ad8e8fec40290a8c8cf145c0deaadf76f80c5163	patch
https://git.kernel.org/stable/c/ab1ff5890c7354afc7be56502fcfbd61f3b7ae4f	patch
https://git.kernel.org/stable/c/25b6821884713a31e2b49fb67b0ebd765b33e0a9	patch
https://git.kernel.org/stable/c/c56f78614e7781aaceca9bd3cb2128bf7d45c3bd	patch
https://git.kernel.org/stable/c/b9e6431cbea8bb1fae8069ed099b4ee100499835	patch
https://git.kernel.org/stable/c/17c1b9807b8a67d676b6dcf749ee932ebaa7f568	patch
https://git.kernel.org/stable/c/d0aefec1b1a1ba2c1d251028dc2c4e5b4ce1fea5	patch
https://git.kernel.org/stable/c/4576100b8cd03118267513cafacde164b498b322	patch
https://cert-portal.siemens.com/productcert/html/ssa-019113.html
https://cert-portal.siemens.com/productcert/html/ssa-082556.html
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The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.