SB2026090108 - Red Hat Enterprise Linux 9 update for runc
Published: September 1, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 3 vulnerabilities.
1) Input validation error (CVE-ID: CVE-2026-32281)
CWE-ID: CWE-20 - Improper input validation
CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to improper input validation in Certificate.Verify in crypto/x509 when validating certificate chains containing a very large number of policy mappings. A remote attacker can present a specially crafted certificate chain to cause a denial of service.
This only affects validation of otherwise trusted certificate chains issued by a root CA in the VerifyOptions.Roots CertPool or in the system certificate pool.
2) Improper Certificate Validation (CVE-ID: CVE-2026-33810)
CWE-ID: CWE-295 - Improper Certificate Validation
CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to bypass certificate name constraints.
The vulnerability exists due to improper certificate validation in the Certificate.Verify function in crypto/x509 when verifying a certificate chain containing excluded DNS constraints and wildcard DNS SANs that use different letter case than the constraint. A remote attacker can present a specially crafted certificate chain to bypass certificate name constraints.
This only affects validation of otherwise trusted certificate chains issued by a root CA in the VerifyOptions.Roots CertPool or in the system certificate pool.
3) Resource exhaustion (CVE-ID: CVE-2026-32280)
CWE-ID: CWE-400 - Resource exhaustion
CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to uncontrolled resource consumption in the Certificate.Verify chain-building logic in crypto/x509 when processing a large number of intermediate certificates supplied through VerifyOptions.Intermediates. A remote attacker can provide a large number of intermediate certificates to cause a denial of service.
This affects both direct users of crypto/x509 and users of crypto/tls.
Remediation
Install update from vendor's website.