CVE-2026-4258Versions of the package sjcl before 1.0.9 are vulnerable to Improper Verification of Cryptographic Signature due to missing point-on-curve…
- 8.7HighCVSS base score
- 0.29%Exploitation in 30 daysEPSS · top 78% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- YesPublic exploitsa reference or SSVC says so
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.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. 2 references of the record are tagged as an exploit. CISA's SSVC rates its exploitation: a proof of concept is public.
Show the exploits2
References tagged exploit2 references
Timeline
ID reserved
By snyk
- 1 day later
· 1 day later
Published
- 5 months later
· 5 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| snykCNA (assigner) | 4.0 | High8.7 | 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 |
| snykCNA (assigner) | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:P |
| NVDNVD · Modified | 4.0 | High7.7 | 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 |
- EPSS (exploitation in 30 days)
- 0.29% · top 78% of all CVEs (12 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.7.
Affected products
sjcl
- affected < 1.0.9
org.webjars.npm:sjcl
- affected < *
Affected packages
From reviewed advisories of the GitHub Advisory Database.
References
References5
- https://security.snyk.io/vuln/SNYK-JS-SJCL-15369617 (opens in a new tab)exploit
- https://security.snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-15751243 (opens in a new tab)
- https://gist.github.com/Kr0emer/2560f98edb10b0b34f2438cd63913c47 (opens in a new tab)exploit
- https://github.com/bitwiseshiftleft/sjcl/blob/master/core/ecc.js%23L454-L461 (opens in a new tab)
- https://github.com/bitwiseshiftleft/sjcl/commit/ee307459972442a17beebc29dc331fffd8aff796 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-12542 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-2w8x-224x-785m (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-4258)Record last updated .