Signature malleability via unchecked EDDSA signature length
Published Aug 2, 2024 · Updated Nov 3, 2025
EDDSA verification in Elliptic 4.0.0 through 6.5.6 allows remote attackers to have malformed Ed25519 signatures accepted. The signature constructor splits decoded bytes into R and S without first requiring the exact two-component length, so removing or appending zero bytes preserves verification. Reachability requires a consuming application to verify attacker-controlled Ed25519 signatures; the resulting effect depends on its use of signature uniqueness.
Summary
What happened
EDDSA verification in Elliptic 4.0.0 through 6.5.6 allows remote attackers to have malformed Ed25519 signatures accepted. The signature constructor splits decoded bytes into R and S without first requiring the exact two-component length, so removing or appending zero bytes preserves verification. Reachability requires a consuming application to verify attacker-controlled Ed25519 signatures; the resulting effect depends on its use of signature uniqueness.
The record
- CVE
- CVE-2024-42459
- Published
- Aug 2, 2024
- Updated
- Nov 3, 2025
- Vendor
- Elliptic Project
- Product
- Elliptic
- Classifications
- CWE-347
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 2, 2024CVE publishedPublication date reported by the CVE source.
- Nov 3, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=6.5.6
What conditions does exploitation require?
What is affected?
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
- Malformed Ed25519 signature test vectorsproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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