cvedb.io
CVE-2026-43968
MEDIUM · CVSS 4
EPSS exploitation probability: 0%
Published 2026-05-11T19:16:25.100 · Last modified 2026-06-17T10:50:08.363

Summary

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 l

Affected products

ninenines — cowlib

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.