CVE intelligence and bounded remediation

CVE-2023-27538 — Haxx Libcurl security vulnerability

High CVSS 7.7

An authentication bypass vulnerability exists in libcurl prior to v8.0.0 where it reuses a previously established SSH connection despite the fact that an SSH option was modified, which should have prevented reuse. libcurl maintains a pool of previously used connections to reuse them for subsequent transfers if the configurations match. However, two SSH settings were omitted from the configuration check, allowing them to match easily, potentially leading to the reuse of an inappropriate connection.

Severity
High
CVSS
7.7 (3.1)
Published
2023-03-30
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-305, CWE-287

Affected products

  • haxx / libcurl
  • fedoraproject / fedora / 36
  • debian / debian_linux / 10.0
  • netapp / active_iq_unified_manager
  • netapp / clustered_data_ontap / 9.0
  • broadcom / brocade_fabric_operating_system_firmware

Showing 6 representative product identities from 13 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Authentication bypass and missing authentication

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Map every affected endpoint and protocol path, including alternate ports, legacy routes, recovery flows, service accounts, and machine-to-machine access.
  • Confirm which deployments enable the affected authentication mode and whether the interface is reachable from untrusted networks.
  • Review session, token, credential, and proxy trust configuration without attempting account takeover.

Remediate safely

  • Apply the supported fix and centralize fail-closed authentication before protected request handling.
  • Remove default or embedded credentials, rotate affected secrets and sessions, and bind authentication decisions to the intended audience and channel.
  • Add negative tests for alternate routes, malformed or absent credentials, recovery flows, and proxy-derived identity.

Authoritative sources

Complete CVE record and remediation plan

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