Service interruption via expensive DHE calculations
Published Aug 26, 2024 · Updated May 12, 2026
DHE key-agreement validation in affected Siemens products allows remote attackers to exhaust server resources through crafted handshakes. The server validates a client public key's order for an approved safe prime by performing unnecessarily expensive modular exponentiation. Exploitation requires an unauthenticated client to offer only DHE and a server configured to permit DHE and validate public-key order.
Summary
What happened
DHE key-agreement validation in affected Siemens products allows remote attackers to exhaust server resources through crafted handshakes. The server validates a client public key's order for an approved safe prime by performing unnecessarily expensive modular exponentiation. Exploitation requires an unauthenticated client to offer only DHE and a server configured to permit DHE and validate public-key order.
The record
- CVE
- CVE-2024-41996
- Published
- Aug 26, 2024
- Updated
- May 12, 2026
- Vendor
- Siemens
- Product
- SCALANCE XRM334 (24 V DC, 12xFO)
- Classifications
- CWE-295, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 26, 2024CVE publishedPublication date reported by the CVE source.
- May 12, 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.
- Affected versionversion=0 <V3.3
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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