CVE-2026-43966 Affecting rabbitmq-server package, versions *


Severity

Recommended
low

Based on Debian security rating.

Threat Intelligence

EPSS
0.25% (17th percentile)

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  • Snyk IDSNYK-DEBIAN13-RABBITMQSERVER-17334381
  • published14 Jun 2026
  • disclosed8 Jun 2026

Introduced: 8 Jun 2026

CVE-2026-43966  (opens in a new tab)

How to fix?

There is no fixed version for Debian:13 rabbitmq-server.

NVD Description

Note: Versions mentioned in the description apply only to the upstream rabbitmq-server package and not the rabbitmq-server package as distributed by Debian. See How to fix? for Debian:13 relevant fixed versions and status.

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. An application that builds a structured HTTP header via cow_http_struct_hd:item/1 (or a higher-level wrapper such as cow_http_hd:wt_protocol/1) from attacker-controlled input can have \r\n injected into the serialized header value. Once on the wire, the injected CRLF terminates the current header and any following bytes are interpreted as a new header, enabling HTTP response splitting.

This issue affects cowlib from 2.9.0.

CVSS Base Scores

version 3.1