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4.3
CVE-2020-36843: ed25519-java Signatures Can Be Altered by Attackers
CVE-2020-36843 · published 1 year ago
Summary
The EdDSA implementation in the ed25519-java library through version 0.3.0 allows attackers to create fake signatures that match a specific message. This means that sensitive information could be tampered with or forged. Update to a fixed version of the library to protect against this risk.
What to do
- Update i2p net.i2p:i2p to version 0.9.39.
- Update debian libeddsa-java to version 0.3.0-2.1.
Affected software
| Ecosystem | Vendor | Product | Affected versions |
|---|---|---|---|
| maven | i2p | net.i2p.crypto:eddsa | <= 0.3.0 |
| maven | i2p | net.i2p:i2p |
< 0.9.39 Fix: upgrade to 0.9.39
|
| Ubuntu:20.04:LTS | canonical | ruby-ed25519 | All versions |
| Ubuntu:25.10 | canonical | libeddsa-java | All versions |
| Debian:13 | debian | libeddsa-java |
< 0.3.0-2.1 Fix: upgrade to 0.3.0-2.1
|
Original advisory text
The implementation of EdDSA in EdDSA-Java (aka ed25519-java) through 0.3.0 exhibits signature malleability and does not satisfy the SUF-CMA (Strong Existential Unforgeability under Chosen Message A...
The implementation of EdDSA in EdDSA-Java (aka ed25519-java) through 0.3.0 exhibits signature malleability and does not satisfy the SUF-CMA (Strong Existential Unforgeability under Chosen Message Attacks) property. This allows attackers to create new valid signatures different from previous signatures for a known message.
References
- https://nvd.nist.gov/vuln/detail/CVE-2020-36843
- https://github.com/i2p/i2p.i2p/commit/d7d1dcb5399c61cf2916ccc45aa25b0209c88712#d...
- https://github.com/advisories/GHSA-p53j-g8pw-4w5f
- https://ubuntu.com/security/CVE-2020-36843 Third Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2020-36843 Third Party Advisory
- https://eprint.iacr.org/2020/1244 Third Party Advisory
- https://github.com/str4d/ed25519-java/issues/82#issue-727629226 Third Party Advisory
- https://security-tracker.debian.org/tracker/CVE-2020-36843 Vendor Advisory
Internet-facing
60 days
Internal
At next upgrade
- Not known to be exploited
- Needs hands-on effort to exploit
- Gives an attacker partial control
Type
CWE-347Improper Verification of Cryptographic Signature
Timeline
Published13 Mar 2025
Updated26 Oct 2026
First seen6 Mar 2026
Sources
GHSA-p53j-g8pw-4w5f · GHSA
CVE-2020-36843 · NVD
UBUNTU-CVE-2020-36843 · OSV
CVE-2020-36843 · OSV
DEBIAN-CVE-2020-36843 · OSV
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