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CVE-2026-43929

8.2 · HIGH

ssrfcheck is a library that checks if a string contains a potential SSRF attack.

Published May 12, 2026CWE-184EPSS 0.36%

Overview

CVE-2026-43929 is a high-severity vulnerability. It was published on May 12, 2026 and has a CVSS 3.1 base score of 8.2 (HIGH).

This vulnerability has a CVSS 3.1 base score of 8.2, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical 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.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

GitHubgithub.com/felippe-regazio/ssrfcheck/security/advisories/GHSA-j4rj-2jr5-m439GitHubgithub.com/felippe-regazio/ssrfcheck/security/advisories/GHSA-j4rj-2jr5-m439

How CyberStrike helps

Frequently asked questions

What is CVE-2026-43929?

CVE-2026-43929 is a high-severity vulnerability. It was published on May 12, 2026 and has a CVSS 3.1 base score of 8.2 (HIGH).

How severe is CVE-2026-43929?

This vulnerability has a CVSS 3.1 base score of 8.2, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2026-43929?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-43929?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-43929 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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