CVE-2026-43929HIGH 8.2EPSS p13.2%
CVE-2026-43929CVE-2026-43929
Description
ssrfcheck is a library that checks if a string contains a potential SSRF attack. In 1.3.0 and earlier, ssrfcheck fails to block Server-Side Request Forgery attacks when the target private IP address is encoded as an IPv4-mapped IPv6 address (e.g. http://[::ffff:127.0.0.1]/). The WHATWG URL parser built into Node.js silently normalizes the IPv4 notation inside the brackets to compressed hex form ([::ffff:7f00:1]) before the library's private-IP regex ever runs. The regex was written to match dot-notation only and therefore never matches any real input — all seven IANA private IPv4 ranges, including the AWS/GCP/Azure metadata address 169.254.169.254, are bypassed. Any application using isSSRFSafeURL() to guard HTTP requests made with user-supplied URLs is fully exposed to SSRF.
Scoring
| CVSS 3.1 | 8.2 (HIGH) |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N |
| EPSS | 0.23% probability of exploitation · percentile 13.2% · 2026-06-18T12:00:27Z |
| Published | 2026-05-12 |
| Last modified | 2026-05-13 |
Underlying weaknesses· 2
References
2
| Type | Target | Confidence | Tier |
|---|---|---|---|
| Weakness | Incomplete List of Disallowed Inputscwe-184 | 0% | live |
| Weakness | Server-Side Request Forgery (SSRF)cwe-918 | 0% | live |
Related by meaning· 6
Nearest entities by semantic similarity across the cs-graph corpus.