CVE-2026-31423
net/sched: sch_hfsc: fix divide-by-zero in rtsc_min()
Description
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.
INFO
Published Date :
April 13, 2026, 2:16 p.m.
Last Modified :
April 18, 2026, 9:16 a.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Widen dsm to u64.
- Replace do_div() with div64_u64().
- Apply the provided patch to the Linux kernel.
- Update the Linux kernel to the patched version.
Public PoC/Exploit Available at Github
CVE-2026-31423 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
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information, practical solutions, and valuable tools related to
CVE-2026-31423.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-31423 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-31423
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
None
Python
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-31423 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-31423 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Apr. 18, 2026
Action Type Old Value New Value Added Reference https://git.kernel.org/stable/c/ab1ff5890c7354afc7be56502fcfbd61f3b7ae4f Added Reference https://git.kernel.org/stable/c/ad8e8fec40290a8c8cf145c0deaadf76f80c5163 -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Apr. 13, 2026
Action Type Old Value New Value Added Description 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. Added Reference https://git.kernel.org/stable/c/17c1b9807b8a67d676b6dcf749ee932ebaa7f568 Added Reference https://git.kernel.org/stable/c/25b6821884713a31e2b49fb67b0ebd765b33e0a9 Added Reference https://git.kernel.org/stable/c/4576100b8cd03118267513cafacde164b498b322 Added Reference https://git.kernel.org/stable/c/b9e6431cbea8bb1fae8069ed099b4ee100499835 Added Reference https://git.kernel.org/stable/c/c56f78614e7781aaceca9bd3cb2128bf7d45c3bd Added Reference https://git.kernel.org/stable/c/d0aefec1b1a1ba2c1d251028dc2c4e5b4ce1fea5