CVE-2026-4258

What it is

Versions of the package sjcl before 1.0.9 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.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of data exposure.

Exploit odds

0.3% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-03-17 06:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-07-28 16:18 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.3% in the next 30 days (EPSS).
• Severity: 7.7 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-03-17 06:16 UTC

Last modified

2026-07-28 16:18 UTC

Exploit probability

0.3% · EPSS, next 30 days

Weakness

CWE-347

Record status

Modified

Affected

• Bitwiseshiftleft Stanford Javascript Crypto Library ≤ 1.0.8

Attack profile CVSS 4.0 · 7.7

Attack vector

Network

Complexity

Low

Attack requirements

None

Privileges needed

None

User interaction

None

Confidentiality

High

Integrity

None

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-4258.md and follow it. Check whether this project is affected by CVE-2026-4258. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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