🛡️ CVE-2026-43966 on Debian — rabbitmq-server

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

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.

Distribution advisory

This page covers CVE-2026-43966 as tracked by Debian, for the package rabbitmq-server. No fixed version has been recorded for this distribution yet.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity low, availability none.

Weakness class

DEBIAN-CVE-2026-43966 is classified as CWE-113: HTTP Response Splitting. Unescaped input reaches an HTTP header, letting an attacker inject line breaks and forge additional headers or responses.

Affected software

DEBIAN-CVE-2026-43966 is recorded against 1 package.

  • rabbitmq-server

Timeline and source

Published on 8 June 2026 and last revised on 18 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

security-tracker.debian.org (Advisory)

CVE-2026-43966 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-06-08
Updated 2026-08-20
Modified 2026-08-18
Fix URL N/A

Affected Packages

Software From version Fixed in
rabbitmq-server — —

Similar Threats

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