Improper signature verification in sjcl
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-347.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | sjcl | before 1.0.9 | 1.0.9 | Patch available | CNA |
| — | org.webjars.npm:sjcl | all versions | — | No fix listed | CNA |
| — | sjcl (npm) | before 1.0.9 | 1.0.9 | Patch available | GHSA-2w8x-224x-785m |
- sjcl Vendor— Affected before 1.0.9 Fixed in 1.0.9 Patch available CNA
- org.webjars.npm:sjcl Vendor— Affected all versions Fixed in — No fix listed CNA
- sjcl (npm) Vendor— Affected before 1.0.9 Fixed in 1.0.9 Patch available GHSA-2w8x-224x-785m
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:bitwiseshiftleft:stanford_javascript_crypto_library:*:*:*:*:*:node.js:*:* | up to 1.0.8 | Vulnerable | Bitwiseshiftleft |
- cpe:2.3:a:bitwiseshiftleft:stanford_javascript_crypto_library:*:*:*:*:*:node.js:*:* Versions up to 1.0.8 Vulnerable ·Bitwiseshiftleft
Remediation
- Fix · CNA sjcl Fixed in 1.0.9
- Fix · GHSA-2w8x-224x-785m sjcl (npm) Fixed in 1.0.9 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-4258
- 2026-10-03 Alias added: GHSA-2w8x-224x-785m
References
Sources
- CVE-2026-4258 · CVE Program
- CVE-2026-4258 · NVD
- FIRST EPSS
- GHSA-2w8x-224x-785m · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences