CVE-2026-87862

HSTS cache import drops longer-lived child

Published Oct 20, 2026 CVSS 3.1 · 8.1 High EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-8927-1 curl vulnerabilities
Ubuntu USN Ubuntu USN USN-8932-1 curl vulnerabilities
Ubuntu USN Ubuntu USN USN-8927-2 curl vulnerabilities
History
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}

cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'}

Type Values Removed Values Added
Description A flaw was found in curl. When importing HTTP Strict Transport Security (HSTS) cache records, loading a parent domain entry configured to include subdomains before a longer-lived subdomain entry silently drops the subdomain policy. Consequently, once the parent policy expires, curl fails to upgrade subsequent connections for the subdomain to HTTPS and transmits unencrypted requests, allowing a network attacker to intercept sensitive data. 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.
Title curl: curl: HSTS cache import drops longer-lived child HSTS cache import drops longer-lived child
References
Type Values Removed Values Added
First Time appeared Curl
Curl curl
Vendors & Products Curl
Curl curl
Type Values Removed Values Added
Description A flaw was found in curl. When importing HTTP Strict Transport Security (HSTS) cache records, loading a parent domain entry configured to include subdomains before a longer-lived subdomain entry silently drops the subdomain policy. Consequently, once the parent policy expires, curl fails to upgrade subsequent connections for the subdomain to HTTPS and transmits unencrypted requests, allowing a network attacker to intercept sensitive data.
Title curl: curl: HSTS cache import drops longer-lived child
Weaknesses CWE-201
References
Metrics threat_severity

None

cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N'}

threat_severity

Low

Weaknesses

Sources

Status
PUBLISHED
Assigner
curl
Published
Updated
Oct 30, 2026, 11:57 AM
Reserved
Sep 9, 2026, 1:17 PM
Status
Awaiting Analysis
Published
Oct 20, 2026, 9:17 PM
Modified
Oct 30, 2026, 12:16 PM
Severity
Low
Public date
Oct 14, 2026, 12:00 PM