CVE-2026-4258 json
sjcl is missing point-on-curve validation in sjcl.ecc.basicKey.publicKey
published 2026-03-17 7 mo ago modified 2026-08-07 3 mo ago also GHSA-2w8x-224x-785m , EUVD-2026-12542
- cvss
- 7.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 17%
- public exploits
- 0
- none known
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.
Patch / fix
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 7 mo ago
Exploit prediction
0.26% chance of exploitation in the next 30 days, higher than 17% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- security.snyk.io https://security.snyk.io/vuln/SNYK-JS-SJCL-15369617 referenced PoC, tagged "exploit" by a source, unverified
- gist.github.com https://gist.github.com/Kr0emer/2560f98edb10b0b34f2438cd63913c47 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.7 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:P |
| CNA | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:P |
| CNA | 4.0 | 7.7 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| CNA | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |
| GitHub | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | sjcl | <1.0.9 |
1.0.9 |
Affected products
- n/a sjcl
- n/a org.webjars.npm:sjcl
Classification
References
-
github.com
/bitwiseshiftleft/sjcl/commit/ee307459972442a17beebc29dc331fffd8aff796
web, patch
-
security.snyk.io
/vuln/SNYK-JS-SJCL-15369617
exploit, web, third-party-advisory
-
gist.github.com
/Kr0emer/2560f98edb10b0b34f2438cd63913c47
exploit, web, mitigation, third-party-advisory
- security.snyk.io /vuln/SNYK-JAVA-ORGWEBJARSNPM-15751243
-
github.com
/bitwiseshiftleft/sjcl/blob/master/core/ecc.js%23L454-L461
broken-link
-
nvd.nist.gov
/vuln/detail/CVE-2026-4258
advisory
-
github.com
/bitwiseshiftleft/sjcl
package
-
github.com
/bitwiseshiftleft/sjcl/blob/master/core/ecc.js#L454-L461
web
Sources
- CVE List CVE-2026-4258
- GitHub Advisory GHSA-2w8x-224x-785m
- NVD CVE-2026-4258
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