What’s Vulnerable › Vulnerabilities

CVE-2026-4258

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-03-17 · updated 2026-07-28
• Weakness: CWE-347

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.

Affected products

• Bitwiseshiftleft Stanford Javascript Crypto Library: through 1.0.8

References

• https://gist.github.com/Kr0emer/2560f98edb10b0b34f2438cd63913c47
• https://github.com/bitwiseshiftleft/sjcl/blob/master/core/ecc.js%23L454-L461
• https://github.com/bitwiseshiftleft/sjcl/commit/ee307459972442a17beebc29dc331fffd8aff796
• https://security.snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-15751243
• https://security.snyk.io/vuln/SNYK-JS-SJCL-15369617
• https://gist.github.com/Kr0emer/2560f98edb10b0b34f2438cd63913c47
• https://security.snyk.io/vuln/SNYK-JS-SJCL-15369617

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