Insertion of Sensitive Information Into Sent Data Affecting curl package, versions [8.18.0,8.21.0)


Severity

Recommended
0.0
medium
0
10

CVSS assessment by Snyk's Security Team. Learn more

Threat Intelligence

EPSS
0.4% (33rd percentile)

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  • Snyk IDSNYK-UNMANAGED-CURL-17808146
  • published3 Jul 2026
  • disclosed3 Jul 2026
  • creditUnknown

Introduced: 3 Jul 2026

CVE-2026-9546  (opens in a new tab)
CWE-201  (opens in a new tab)

How to fix?

Upgrade curl to version 8.21.0 or higher.

Overview

curl is a command line tool and library for transferring data with URL syntax, supporting DICT, FILE, FTP, FTPS, GOPHER, GOPHERS, HTTP, HTTPS, IMAP, IMAPS, LDAP, LDAPS, MQTT, POP3, POP3S, RTMP, RTMPS, RTSP, SCP, SFTP, SMB, SMBS, SMTP, SMTPS, TELNET and TFTP. libcurl offers a myriad of powerful features.

Affected versions of this package are vulnerable to Insertion of Sensitive Information Into Sent Data due to the improper clearing of the CURLOPT_REFERER option. An attacker can cause sensitive information to be disclosed by forcing the reuse and transmission of a previous referer header to unintended servers.

CVSS Base Scores

version 4.0
version 3.1