Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') vulnerability in ninenines cowlib allows HTTP response splitting via non-VCHAR bytes in structured-fields…
Medium CVSS 5.3
Summary
Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') vulnerability in ninenines cowlib allows HTTP response splitting via non-VCHAR bytes in structured-fields string values. cow_http_struct_hd:escape_string/2 in cowlib only escapes \ and ", passing all other bytes through verbatim. This creates an encoder/decoder asymmetry: the matching parser accepts only printable ASCII (0x20–0x7E, excluding " and \), but the encoder emits any byte including CR and LF…
In-depth triage
No in-depth report has been generated yet (DR-003 v2 AI pipeline is under construction).
Affected products
- :
Sources
- NVD DATABASE
Original Links
- https://cna.erlef.org/cves/CVE-2026-43966.html Third Party Advisory
- https://github.com/ninenines/cowboy/commit/f77cb9b5e730e300fffb551db1ba5d1c4ed878ef Patch
- https://github.com/ninenines/gun/commit/4f35609eb37109b106a863fc9ba83d7ee64e3e42 Patch
- https://osv.dev/vulnerability/EEF-CVE-2026-43966 Third Party Advisory
Timeline
- nvd_ingest NVD