SB2026101440 - Multiple vulnerabilities in cURL

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Main Vulnerability Database SB2026101440

SB2026101440 - Multiple vulnerabilities in cURL

Published: October 14, 2026

Security Bulletin ID SB2026101440
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 3
Exploitation vector Remote access
Highest impact Information disclosure

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 3 vulnerabilities.


1) Command injection (CVE-ID: CVE-2026-87864)

CWE-ID: CWE-77 - Command injection

CVSSv4: 0 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote user to inject and execute IMAP commands within an authenticated session.

The vulnerability exists due to improper handling of a length parameter inconsistency in curl's IMAP APPEND implementation when processing uploads. A remote user can supply upload data whose line-ending conversion expands it beyond the advertised literal length to inject and execute IMAP commands within an authenticated session.

Exploitation requires CURLOPT_CRLF to be enabled.


2) Exposure of Data Element to Wrong Session (CVE-ID: CVE-2026-86411)

CWE-ID: CWE-488 - Exposure of Data Element to Wrong Session

CVSSv4: 0 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a local user to perform FTP transfers under another handle's client-certificate identity.

The vulnerability exists due to exposure of authentication state to the wrong session in libcurl's FTP connection reuse logic when reusing a pooled control connection previously upgraded with STARTTLS and authenticated using a client certificate. A local user can initiate an ftp:// transfer configured with CURLUSESSL_NONE using that connection pool to perform FTP transfers under another handle's client-certificate identity.

The second handle performs neither a new TLS handshake nor a new FTP login.


3) Insertion of Sensitive Information Into Sent Data (CVE-ID: CVE-2026-86409)

CWE-ID: CWE-201 - Insertion of Sensitive Information Into Sent Data

CVSSv4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to disclose an access-key identifier and a request-bound signature.

The vulnerability exists due to failure to disable SigV4 authentication in libcurl's SigV4 authentication handling when an application sets CURLOPT_AWS_SIGV4 to NULL and reuses the same easy handle while retaining CURLOPT_USERPWD credentials. A remote attacker can influence the destination URL of a subsequent request to disclose an access-key identifier and a request-bound signature.

The secret key is not transmitted. This flaw is not accessible through the curl command line tool.


Remediation

Install update from vendor's website.

References