GHSA-mj4x-wcxf-hm8x · Severity: medium · Ecosystem: rubygems — Json-jwt did not verify the cryptographic signature for data
Nov json-jwt version >= 0.5.0 && < 1.9.4 contains a CWE-347: Improper Verification of Cryptographic Signature vulnerability in Decryption of AES-GCM encrypted JSON Web Tokens that can result in Attacker can forge a authentication tag. This attack appear to be exploitable via network connectivity. This vulnerability appears to have been fixed in 1.9.4 and later.
Conclusion & alert: CVE-2018-1000539 is rated Low Risk (39.6/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.78%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 0.14% | 0.78% | +0.64% |
| 2 | 2025-03-30 | 0.20% | 0.14% | -0.06% |
| 3 | 2025-03-29 | — | 0.20% | — |
Full EPSS history (6 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 5.3 | 3.0 | MEDIUM |
|
3.9 | 1.4 | [email protected] |
| 5.0 | 2.0 | MEDIUM |
|
10.0 | 2.9 | [email protected] |
GHSA-mj4x-wcxf-hm8x · Severity: medium · Ecosystem: rubygems — Json-jwt did not verify the cryptographic signature for data
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
not yet assigned | CVE-2018-1000539 not yet assigned priority: Debian including 1 source packages (ruby-json-jwt), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. | https://security-tracker.debian.org/tracker/CVE-2018-1000539 |
ubuntu
|
medium | CVE-2018-1000539 medium priority: Ubuntu including 1 source packages (ruby-json-jwt), 16 status rows across 16 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 12, DNE 2, needed 1, released 1. | https://ubuntu.com/security/CVE-2018-1000539 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| json-jwt_project | json-jwt | >= 0.5.0, < 1.9.4 | cpe:2.3:a:json-jwt_project:json-jwt:*:*:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| https://github.com/nov/json-jwt/pull/62 | Third Party Advisory |
| https://www.debian.org/security/2018/dsa-4283 |