CVE-2026-4258

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.

References

https://security.snyk.io/vuln/SNYK-JS-SJCL-15369617

https://github.com/bitwiseshiftleft/sjcl/commit/ee307459972442a17beebc29dc331fffd8aff796

https://github.com/bitwiseshiftleft/sjcl/blob/master/core/ecc.js%23L454-L461

https://gist.github.com/Kr0emer/2560f98edb10b0b34f2438cd63913c47

Details

Source: Mitre, NVD

Risk Information

CVSS v2

CVSS v3

CVSS v4