CVE-2026-43972
7.2 · HIGHOverview
CVE-2026-43972 is a high-severity vulnerability affecting ninenines gun. It was published on June 8, 2026 and has a CVSS 3.1 base score of 7.2 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.2, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
Origin Validation Error vulnerability in ninenines gun (gun_http2 module) allows cross-origin cookie injection via unvalidated HTTP/2 PUSH_PROMISE authority.
In gun_http2:push_promise_frame/7, the :authority pseudo-header from an incoming PUSH_PROMISE frame is stored verbatim into the promised stream record without checking that it matches the connection's origin. When gun_http2:headers_frame/9 later processes the response headers for the promised stream, it calls gun_cookies:set_cookie_header/7 with the unvalidated server-supplied authority before any status branching and before user code can act. This violates RFC 7540 §10.6 / RFC 9113 §8.4, which require receivers to treat as a protocol error any push for a resource the server is not authoritative for.
A malicious or compromised HTTP/2 server can plant cookies scoped to arbitrary third-party domains into the client's shared cookie store. This enables session fixation attacks against those domains and, if the planted cookie overrid
Remediation
Check the references section for vendor advisories and patches from ninenines. Update gun to the latest patched version. 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.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| ninenines | gun | >= 2.0.0, < 2.4.0 | Affected |
Frequently Asked Questions
What is CVE-2026-43972?
CVE-2026-43972 is a high-severity vulnerability affecting ninenines gun. It was published on June 8, 2026 and has a CVSS 3.1 base score of 7.2 (HIGH).
How severe is CVE-2026-43972?
This vulnerability has a CVSS 3.1 base score of 7.2, 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-2026-43972?
Check the references section for vendor advisories and patches from ninenines. Update gun to the latest patched version. 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-2026-43972?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-43972 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
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