CVE-2025-40281

Kernel service interruption via oversized SCTP RTO shift

Published Dec 6, 2025 · Updated Jun 16, 2026

Incorrect bit shifting in the Linux SCTP stack and Siemens RST2428P before V4.0 allows local users to interrupt service. sctp_transport_update_rto shifts a 32-bit unsigned value using an oversized exponent derived from mutable rto_alpha or rto_beta sysctl settings without first rejecting the invalid value. Reachability requires high local privileges and unusually large SCTP RTO settings; the published impact is limited to availability.

CVSS severity4.4
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect bit shifting in the Linux SCTP stack and Siemens RST2428P before V4.0 allows local users to interrupt service. sctp_transport_update_rto shifts a 32-bit unsigned value using an oversized exponent derived from mutable rto_alpha or rto_beta sysctl settings without first rejecting the invalid value. Reachability requires high local privileges and unusually large SCTP RTO settings; the published impact is limited to availability.

The record

CVE
CVE-2025-40281
Published
Dec 6, 2025
Updated
Jun 16, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-1335, T1499
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Dec 6, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 16, 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=3.16
  2. Affected versionversion=b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b <0e0413e3315199b23ff4aec295e256034cd0a6e4
  3. Affected versionversion=b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b <1534ff77757e44bcc4b98d0196bc5c0052fce5fa
  4. Affected versionversion=b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b <1cfa4eac275cc4875755c1303d48a4ddfe507ca8
  5. Affected versionversion=b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b <834e65be429c0fa4f9bb5945064bd57f18ed2187
  6. Affected versionversion=b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b <aaba523dd7b6106526c24b1fd9b5fc35e5aaa88d
  7. Affected versionversion=b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b <abb086b9a95d0ed3b757ee59964ba3c4e4b2fc1a
  8. Affected versionversion=b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b <d0d858652834dcf531342c82a0428170aa7c2675
  9. Affected versionversion=b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b <ed71f801249d2350c77a73dca2c03918a15a62fe

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=3.16; version=b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b <0e0413e3315199b23ff4aec295e256034cd0a6e4; version=b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b <1534ff77757e44bcc4b98d0196bc5c0052fce5fa; version=b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b <1cfa4eac275cc4875755c1303d48a4ddfe507ca8; version=b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b <834e65be429c0fa4f9bb5945064bd57f18ed2187; version=b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b <aaba523dd7b6106526c24b1fd9b5fc35e5aaa88d; version=b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b <abb086b9a95d0ed3b757ee59964ba3c4e4b2fc1a; version=b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b <d0d858652834dcf531342c82a0428170aa7c2675; version=b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b <ed71f801249d2350c77a73dca2c03918a15a62fe
Siemens · RUGGEDCOM RST2428Pversion=0 <V4.0

Published CVSS scores

4.4Siemens ProductCERTCVSS:3.1/AV:L/AC:L/PR:H/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.

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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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1335Incorrect Bitwise Shift of Integer
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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