Service interruption via unpulled IP tunnel header
Published Apr 17, 2024 · Updated Aug 12, 2026
Improper input validation in affected Linux kernels allows remote attackers to interrupt service through malformed IP tunnel packets. In ip_tunnel_rcv, the receive path uses the inner network header without first ensuring that the required bytes are present in linear packet memory and without restoring the header pointer after a pull. Reachability requires an active IP tunnel receive path; the resulting uninitialized read during ECN decapsulation can crash the kernel, including the kernel in the affected Siemens subsystem.
Summary
What happened
Improper input validation in affected Linux kernels allows remote attackers to interrupt service through malformed IP tunnel packets. In ip_tunnel_rcv, the receive path uses the inner network header without first ensuring that the required bytes are present in linear packet memory and without restoring the header pointer after a pull. Reachability requires an active IP tunnel receive path; the resulting uninitialized read during ECN decapsulation can crash the kernel, including the kernel in the affected Siemens subsystem.
The record
- CVE
- CVE-2024-26882
- Published
- Apr 17, 2024
- Updated
- Aug 12, 2026
- Vendor
- Siemens
- Product
- SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
- Classifications
- CWE-457, CWE-20, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 17, 2024CVE publishedPublication date reported by the CVE source.
- Aug 12, 2026Record updatedLatest update available in the CVE record.
Exploitability
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Is a vulnerable build present?
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- Affected versionversion=0 <*
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What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
Public exploit references
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Technologies
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Your stack
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