CVE-2026-87864
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curl IMAP Command Injection via CURLOPT_CRLF

Publication date: 2026-10-20

Last updated on: 2026-10-30

Assigner: curl

Description
Enabling `CURLOPT_CRLF` causes curl to advertise the raw input byte count in the `IMAP APPEND {N}` literal while transmitting line-ending expanded data. The server reads only $N$ bytes for the payload, causing the remaining overflow bytes to be interpreted and executed as pipelined IMAP commands within the authenticated session.

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Meta Information

Published
2026-10-20
Last Modified
2026-10-30
Generated
2026-11-10
AI Q&A
2026-10-21
EPSS Evaluated
2026-11-08
NVD
CVE-2026-87864

Affected Vendors & Products

Showing 114 associated CPEs
Vendor Product Version / Range
curl curl 8.21.0
curl curl 8.20.0
curl curl 8.19.0
curl curl 8.18.0
curl curl 8.17.0
curl curl 8.16.0
curl curl 8.15.0
curl curl 8.14.1
curl curl 8.14.0
curl curl 8.13.0
curl curl 8.12.1
curl curl 8.12.0
curl curl 8.11.1
curl curl 8.11.0
curl curl 8.10.1
curl curl 8.10.0
curl curl 8.9.1
curl curl 8.9.0
curl curl 8.8.0
curl curl 8.7.1
curl curl 8.7.0
curl curl 8.6.0
curl curl 8.5.0
curl curl 8.4.0
curl curl 8.3.0
curl curl 8.2.1
curl curl 8.2.0
curl curl 8.1.2
curl curl 8.1.1
curl curl 8.1.0
curl curl 8.0.1
curl curl 8.0.0
curl curl 7.88.1
curl curl 7.88.0
curl curl 7.87.0
curl curl 7.86.0
curl curl 7.85.0
curl curl 7.84.0
curl curl 7.83.1
curl curl 7.83.0
curl curl 7.82.0
curl curl 7.81.0
curl curl 7.80.0
curl curl 7.79.1
curl curl 7.79.0
curl curl 7.78.0
curl curl 7.77.0
curl curl 7.76.1
curl curl 7.76.0
curl curl 7.75.0
curl curl 7.74.0
curl curl 7.73.0
curl curl 7.72.0
curl curl 7.71.1
curl curl 7.71.0
curl curl 7.70.0
curl curl 7.69.1
curl curl 7.69.0
curl curl 7.68.0
curl curl 7.67.0
curl curl 7.66.0
curl curl 7.65.3
curl curl 7.65.2
curl curl 7.65.1
curl curl 7.65.0
curl curl 7.64.1
curl curl 7.64.0
curl curl 7.63.0
curl curl 7.62.0
curl curl 7.61.1
curl curl 7.61.0
curl curl 7.60.0
curl curl 7.59.0
curl curl 7.58.0
curl curl 7.57.0
curl curl 7.56.1
curl curl 7.56.0
curl curl 7.55.1
curl curl 7.55.0
curl curl 7.54.1
curl curl 7.54.0
curl curl 7.53.1
curl curl 7.53.0
curl curl 7.52.1
curl curl 7.52.0
curl curl 7.51.0
curl curl 7.50.3
curl curl 7.50.2
curl curl 7.50.1
curl curl 7.50.0
curl curl 7.49.1
curl curl 7.49.0
curl curl 7.48.0
curl curl 7.47.1
curl curl 7.47.0
curl curl 7.46.0
curl curl 7.45.0
curl curl 7.44.0
curl curl 7.43.0
curl curl 7.42.1
curl curl 7.42.0
curl curl 7.41.0
curl curl 7.40.0
curl curl 7.39.0
curl curl 7.38.0
curl curl 7.37.1
curl curl 7.37.0
curl curl 7.36.0
curl curl 7.35.0
curl curl 7.34.0
curl curl 7.33.0
curl curl 7.32.0
curl curl 7.31.0
curl curl 7.30.0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-130 The product parses a formatted message or structure, but it does not handle or incorrectly handles a length field that is inconsistent with the actual length of the associated data.

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Executive Summary

This vulnerability occurs when curl's CURLOPT_CRLF option is enabled. It causes curl to report the raw byte count of input data in IMAP APPEND commands while actually sending line-ending expanded data. The IMAP server reads only the reported byte count, leaving extra bytes to be misinterpreted as new IMAP commands within an authenticated session.

Detection Guidance

This vulnerability is specific to curl versions using CURLOPT_CRLF. To detect it, check if curl is installed and inspect its version for affected releases. Use commands like 'curl --version' to verify the version. If curl is used in IMAP operations with CURLOPT_CRLF enabled, review configurations for this option.

Impact Analysis

An attacker could exploit this to inject unauthorized IMAP commands into your authenticated session. This may allow them to read, modify, or delete emails, or perform other actions on your behalf without proper authorization.

Compliance Impact

This vulnerability could potentially violate compliance with GDPR and HIPAA by enabling unauthorized command execution within authenticated IMAP sessions. Unauthorized access or manipulation of data could lead to data breaches, compromising personal or sensitive information.

Mitigation Strategies

Disable the CURLOPT_CRLF option in curl to prevent the raw input byte count advertisement and line-ending expansion issue.

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