CVE-2024-49977

Kernel crash via zero-rate CBS division

Published Oct 21, 2024 · Updated May 23, 2026

Division by zero in Linux stmmac traffic control allows local users to crash the kernel by disabling a configured CBS qdisc. The stmmac_tc_setup_cbs path leaves port_transmit_rate_kbps at zero when CBS offload is disabled, then passes that value as the divisor to div_s64. Reachability requires local traffic-control privileges and stmmac-backed hardware; the bounded consequence is a kernel crash and service interruption.

CVSS severity5.5
Medium
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Division by zero in Linux stmmac traffic control allows local users to crash the kernel by disabling a configured CBS qdisc. The stmmac_tc_setup_cbs path leaves port_transmit_rate_kbps at zero when CBS offload is disabled, then passes that value as the divisor to div_s64. Reachability requires local traffic-control privileges and stmmac-backed hardware; the bounded consequence is a kernel crash and service interruption.

The record

CVE
CVE-2024-49977
Published
Oct 21, 2024
Updated
May 23, 2026
Vendor
Siemens
Product
SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family
Classifications
CWE-20
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 21, 2024CVE publishedPublication date reported by the CVE source.
  2. May 23, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <V3.2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Siemens · SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 familyversion=0 <V3.2
Siemens · SIMATIC S7-1500 TM MFP - GNU/Linux subsystemversion=0 <*
The Linux Kernel Organization · Linuxversion=2145583e5995598f50d66f8710c86bb1e910ac46 <b0da9504a528f05f97d926b4db74ff21917a33e9; version=5.10.221 <5.10.227; version=5.15.162 <5.15.168; version=521d42a1c24d638241220d4b9fa7e7a0ed02b88e <5d43e1ad4567d67af2b42d3ab7c14152ffed25c6; version=6.10; version=6.1.96 <6.1.113; version=6.6.36 <6.6.55; version=6.9.7 <6.10; version=a71b686418ee6bcb6d6365f7f6d838d9874d9c64 <03582f4752427f60817d896f1a827aff772bd31e; version=b4bca4722fda928810d024350493990de39f1e40 <e33fe25b1efe4f2e6a5858786dbc82ae4c44ed4c; version=b8c43360f6e424131fa81d3ba8792ad8ff25a09e <675faf5a14c14a2be0b870db30a70764df81e2df; version=b8c43360f6e424131fa81d3ba8792ad8ff25a09e <837d9df9c0792902710149d1a5e0991520af0f93; version=b8c43360f6e424131fa81d3ba8792ad8ff25a09e <e297a2bf56d12fd7f91a0c209eb6ea84361f3368; version=f01782804147a8c21f481b3342c83422c041d2c0
Siemens · SCALANCE XCM/XRM/XCH/XRH-300 familyversion=0 <V3.2
Siemens · RUGGEDCOM RST2428Pversion=0 <V3.2

Published CVSS scores

5.5Siemens ProductCERTCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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