CVE-2026-4258

HIGH
7.5
CVSS Score
Published: March 17, 2026 at 05:00 AM UTC
Updated: July 28, 2026 at 04:35 PM UTC
1 product affected across 1 vendorStanford JavaScript Crypto Library

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Severity
HIGH7.5
Exploit prediction
EPSS 0.3%
SSVC
PoC

Description

All versions of the package sjcl are vulnerable to Improper Verification of Cryptographic Signature due to missing point-on-curve validation in sjcl.ecc.basicKey.publicKey(). An attacker can recover a victim's ECDH private key by sending crafted off-curve public keys and observing ECDH outputs. The dhJavaEc() function directly returns the raw x-coordinate of the scalar multiplication result (no hashing), providing a plaintext oracle without requiring any decryption feedback.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v ≤ 1.0.8v < 1.0.9
Affected range stops below 1.0.9, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHsnyk
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-347CWE-325

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