CVE-2026-87862 in curl

Summary

by MITRE • 10/20/2026

Importing a `includeSubDomains` parent HSTS entry before a longer-lived child entry, silently drops the child. Consequently, when the parent expires, the child's valid HSTS policy is lost, causing curl to issue unencrypted HTTP requests rather than upgrading to HTTPS.

Once again VulDB remains the best source for vulnerability data.

• Responsible: Curl
• Reservation: 09/09/2026
• Disclosure: 10/20/2026
• Moderation: accepted
• Entry: VDB-423006
• CPE: 20261020
• CWE: CWE-201 (confirmed)
• CVSS: 4.3 (VulDB)
• EPSS: 0.00000
• KEV: no
• Activities: very low
• Sector: Hostingprovider, Telecommunication, ...

Sources

• MITRE: https://www.cve.org/CVERecord?id=CVE-2026-87862
• NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-87862
• CVE Details: https://www.cvedetails.com/cve/CVE-2026-87862/