CVE-2026-43968
4.0 · MEDIUMOverview
CVE-2026-43968 is a medium-severity vulnerability affecting ninenines cowlib. It was published on May 11, 2026 and has a CVSS 3.1 base score of 4.0 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 4.0, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
Improper Neutralization of CRLF Sequences ('CRLF Injection') vulnerability in ninenines cowlib allows SSE event splitting and injection via unvalidated field values.
cow_sse:event/1 in cowlib guards the id and event fields against \n but not against bare \r, and the internal prefix_lines/2 function used for data and comment fields splits only on \n. Because the SSE specification requires decoders to treat \r\n, \r, and \n as equivalent line terminators, an attacker who controls any of these fields can inject additional SSE lines and forge a complete event with an arbitrary event type and data payload on the receiving end. In typical deployments where browser EventSource clients or other SSE consumers dispatch on event.type and render event.data, this enables event splitting, client-side logic manipulation, and stored-XSS-equivalent behaviour when event data is inserted into the DOM.
This issue affects cowlib from 2.6.0 before 2.16.1.
Remediation
Check the references section for vendor advisories and patches from ninenines. Update cowlib 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 | cowlib | >= 2.6.0, < 2.16.1 | Affected |
Frequently Asked Questions
What is CVE-2026-43968?
CVE-2026-43968 is a medium-severity vulnerability affecting ninenines cowlib. It was published on May 11, 2026 and has a CVSS 3.1 base score of 4.0 (MEDIUM).
How severe is CVE-2026-43968?
This vulnerability has a CVSS 3.1 base score of 4.0, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-43968?
Check the references section for vendor advisories and patches from ninenines. Update cowlib 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-2026-43968?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-43968 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
AI agents map your attack surface to find vulnerabilities like this one.
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