CVE-2026-4258 Details
Description
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.
A vulnerability exists in all versions of the Stanford JavaScript Crypto Library (SJCL) package that supports elliptic curve cryptography (ECC), specifically versions 1.0.0 through 1.0.8. The issue arises from improper validation of points on the curve in the `sjcl.ecc.basicKey.publicKey()` function. This flaw allows an attacker to recover a victim's Elliptic Curve Diffie-Hellman (ECDH) private key by sending crafted off-curve public keys and analyzing the ECDH output. The `dhJavaEc()` function exacerbates the issue by returning the raw x-coordinate of the scalar multiplication result without any hashing, effectively creating a plaintext oracle that does not require decryption feedback.
Users are advised to update to SJCL version 1.0.9, in which this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Mar 17, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://gist.github.com/Kr0emer/2560f98edb10b0b34f2438cd63913c47 | CISA-ADP | ExploitMitigationThird Party Advisory |
| https://security.snyk.io/vuln/SNYK-JS-SJCL-15369617 | CISA-ADP | ExploitThird Party Advisory |
| https://gist.github.com/Kr0emer/2560f98edb10b0b34f2438cd63913c47 | [email protected] | ExploitMitigationThird Party Advisory |
| https://github.com/bitwiseshiftleft/sjcl/blob/master/core/ecc.js%23L454-L461 | [email protected] | Broken Link |
| https://github.com/bitwiseshiftleft/sjcl/commit/ee307459972442a17beebc29dc331fffd8aff796 | [email protected] | Patch |
| https://security.snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-15751243 | [email protected] | |
| https://security.snyk.io/vuln/SNYK-JS-SJCL-15369617 | [email protected] | ExploitThird Party Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-325 | Missing Cryptographic Step | CISA-ADP |
| CWE-347 | Improper Verification of Cryptographic Signature | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| bitwiseshiftleft stanford javascript crypto library | <= 1.0.8 |
CPE
Remediation
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Change History
6 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 28, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Jun 3, 2026 | Initial Analysis | [email protected] |
| Mar 17, 2026 | CVE Modified | CISA-ADP |
| Mar 17, 2026 | New CVE Received | [email protected] |