SB20261015155 - Fedora 43 update for curl
Published: October 15, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 5 vulnerabilities.
1) Authentication Bypass by Primary Weakness (CVE-ID: CVE-2026-8932)
CWE-ID: CWE-305 - Authentication Bypass by Primary Weakness
CVSSv4: 5.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote user to bypass client certificate authentication.
The vulnerability exists due to authentication bypass by primary weakness in libcurl connection reuse logic when reusing a previously established connection after changing mTLS client certificate settings. A remote user can reuse a connection with mismatched client certificate configuration to bypass client certificate authentication.
The issue affects libcurl and does not affect the curl command line tool.
2) Improper restriction of communication channel to intended endpoints (CVE-ID: CVE-2026-13608)
CWE-ID: CWE-923 - Improper Restriction of Communication Channel to Intended Endpoints
CVSSv4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to bypass LDAP server authentication.
The vulnerability exists due to improper restriction of communication channel to intended endpoints in the libcurl SASL negotiation for LDAP authentication when processing an incomplete OpenLDAP SASL handshake sequence. A remote attacker can inject a premature or shortcut response to bypass LDAP server authentication.
The issue only occurs when the OpenLDAP backend is used, and LDAPS is not affected.
3) Improper Certificate Validation (CVE-ID: CVE-2026-80230)
CWE-ID: CWE-295 - Improper Certificate Validation
CVSSv4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to bypass public key pinning.
The vulnerability exists due to improper certificate validation in libcurl and the curl command line tool when establishing TLS connections with CURLOPT_PINNEDPUBLICKEY configured and peer and host verification disabled. A remote attacker can present a connection without a server certificate to bypass public key pinning.
This issue is present only when curl is built with OpenSSL or a fork such as BoringSSL, AWS-LC, LibreSSL, or QuicTLS, and the insecure configuration also permits certificate-less connections.
4) Insertion of Sensitive Information Into Sent Data (CVE-ID: CVE-2026-80255)
CWE-ID: CWE-201 - Insertion of Sensitive Information Into Sent Data
CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to improper cookie attribute handling in the Set-Cookie header processing logic when parsing a Set-Cookie header that uses a tab immediately before the Secure attribute. A remote attacker can send a specially crafted Set-Cookie header to disclose sensitive information.
The issue can cause a cookie to be stored without its Secure flag and then be sent over plaintext HTTP on subsequent requests to the same host.
5) Use-after-free (CVE-ID: CVE-2026-80229)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 2.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to use-after-free in libcurl multi interface connection reuse handling when performing transfers over pooled TLS connections with OpenSSL 3 providers. A remote user can trigger premature easy handle destruction during connection reuse to cause a denial of service.
This affects libcurl built with OpenSSL 3+ provider configurations and also impacts the curl command line tool.
Remediation
Install update from vendor's website.