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CVE-2020-36843

CVE-2020-36843:
Ed25519 Signature Malleability in ed25519-java Due to Missing Scalar Range Check

4.3

CVSS Score
3.1

Basic Information

CVE ID
CVE-2020-36843
GHSA ID
GHSA-p53j-g8pw-4w5f
EPSS Score
0.00652%
CWE
CWE-347
Published
3/13/2025
Updated
3/13/2025
KEV Status
No
Technology
TechnologyJava

Technical Details

CVSS Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Package NameEcosystemVulnerable VersionsFirst Patched Version
net.i2p.crypto:eddsamaven<= 0.3.0
net.i2p:i2pmaven< 0.9.390.9.39

Vulnerability Intelligence
Miggo AIMiggo AI

Miggo AIRoot Cause Analysis

The vulnerability stems from missing scalar range validation during signature verification. The commit d7d1dcb adds a critical check comparing 'S' against EdDSABlinding.ORDER in EdDSAEngine.java's verification logic. The pre-patch code in x_engineVerify() processed the 'S' value without this validation, enabling signature malleability. The CVE description and academic paper both confirm this missing check as the root cause. The high confidence comes from direct evidence in the patch diff and vulnerability descriptions linking the missing check to SUF-CMA violations.

Vulnerable functions

Only Mi**o us*rs **n s** t*is s**tion

WAF Protection Rules

WAF Rule

T** impl*m*nt*tion o* ***S* in ***S*-J*v* (*k* *******-j*v*) t*rou** *.*.* *x*i*its si*n*tur* m*ll***ility *n* *o*s not s*tis*y t** SU*-*M* (Stron* *xist*nti*l Un*or****ility un**r **os*n M*ss*** *tt**ks) prop*rty. T*is *llows *tt**k*rs to *r**t* n*w

Reasoning

T** vuln*r**ility st*ms *rom missin* s**l*r r*n** v*li**tion *urin* si*n*tur* v*ri*i**tion. T** *ommit `*******` ***s * *riti**l ****k *omp*rin* 'S' ***inst `***S**lin*in*.OR**R` in `***S**n*in*.j*v*`'s v*ri*i**tion lo*i*. T** pr*-p*t** *o** in `x_*n