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Findings

CVE-2023-27533

A vulnerability in input validation exists in curl <8.0 during communication using the TELNET protocol may allow an attacker to pass on maliciously crafted user name a…

Published Mar 30, 2023 · corrected/updated Oct 14, 2026 · haxx curl · evidence confidence high

A vulnerability in input validation exists in curl <8.0 during communication using the TELNET protocol may allow an attacker to pass on maliciously crafted user name and "telnet options" during server negotiation. The lack of proper input scrubbing allows an attacker to send content or perform option negotiation without the application's intent. This vulnerability could be exploited if an application allows user input, thereby enabling attackers to execute arbitrary code on the system.

Grounded briefings

Catalog interpretations for three audiences. Each brief cites ingested metadata and the original advisories below. They are not independent research and they do not invent exploit steps.

Executive

CVE-2023-27533 is a high public vulnerability record for haxx curl. It is not currently listed in the CISA Known Exploited catalog. Check the linked vendor or CERT advisories for patch status. This summary is a catalog interpretation of the ingested metadata and cites the original advisories below.

System administrator

Identify whether haxx curl is in your estate, then compare installed versions with the affected ranges. Affected packages or ranges on record: fedoraproject/fedora (36); haxx/curl; netapp/active iq unified manager; netapp/clustered data ontap (9.0). Check the linked vendor or CERT advisories for patch status. Prefer the vendor or distribution advisory linked in Sources before changing production systems. This is a catalog interpretation, not a runbook.

Security analyst

Signals on file: CVSS 8.8, EPSS 2.2%. It is not currently listed in the CISA Known Exploited catalog. Weakness classes: CWE-74, CWE-75. Sources contributing to this record: cve_org, epss, nvd. Public exploit references, when present, are outbound links only and are not proof of active exploitation. This is a catalog interpretation of stored metadata.

Exploitation and remediation

  • Exploitation evidence

    Not listed as known exploited in CISA KEV. Not in the CISA KEV catalog.

  • Patch and remediation

    No required-action text is stored yet. Use the vendor or CERT links in Sources for patch availability.

  • Safe detection guidance

    Compare installed versions with the affected ranges below and verify the advisory from the original publisher. This site stores metadata and outbound links only; it does not ship exploit code or proof-of-concept payloads.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 30, 2023 · NIST NVD

    Detected

    A vulnerability in input validation exists in curl <8.0 during communication using the TELNET protocol may allow an attacker to pass on maliciously crafted user name and "telnet options" during server negotiation. The lack of proper input scrubbing allows an attacker to send content or perform option negotiation without the application's intent. This vulnerability could be exploited if an applicat

  2. Oct 14, 2026 · NIST NVD

    Updated

    A vulnerability in input validation exists in curl <8.0 during communication using the TELNET protocol may allow an attacker to pass on maliciously crafted user name and "telnet options" during server negotiation. The lack of proper input scrubbing allows an attacker to send content or perform option negotiation without the application's intent. This vulnerability could be exploited if an applicat

Affected

  • cpe fedoraproject/fedora36
  • cpe haxx/curlversion unspecified
  • cpe netapp/active iq unified managerversion unspecified
  • cpe netapp/clustered data ontap9.0
  • cpe netapp/h300s firmwareversion unspecified
  • cpe netapp/h410s firmwareversion unspecified
  • cpe netapp/h500s firmwareversion unspecified
  • cpe netapp/h700s firmwareversion unspecified
  • cpe splunk/universal forwarderversion unspecified

Sources

  • CVE.orgVulnerability recordCVE-2023-27533

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2023-27533

    30-day exploitation probability 2.2%

    first.org
  • NIST NVDVulnerability recordCVE-2023-27533

    A vulnerability in input validation exists in curl <8.0 during communication using the TELNET protocol may allow an attacker to pass on maliciously crafted user name and "telnet options" during server negotiation. The lack of proper input scrubbing allows an attacker to send cont

    nvd.nist.gov

References