CVE-2022-43551

curl: HSTS bypass via IDN

Published Dec 23, 2022 CVSS 3.1 · 7.5 High EPSS 16.6% KEV · Not listed
Description
A vulnerability exists in curl <7.87.0 HSTS check that could be bypassed to trick it to keep using HTTP. Using its HSTS support, curl can be instructed to use HTTPS instead of using an insecure clear-text HTTP step even when HTTP is provided in the URL. However, the HSTS mechanism could be bypassed if the host name in the given URL first uses IDN characters that get replaced to ASCII counterparts as part of the IDN conversion. Like using the character UTF-8 U+3002 (IDEOGRAPHIC FULL STOP) instead of the common ASCII full stop (U+002E) `.`. Then in a subsequent request, it does not detect the HSTS state and makes a clear text transfer. Because it would store the info IDN encoded but look for it IDN decoded.

Analysis

No analysis available yet

Remediation

No remediation available yet

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-5788-1 curl vulnerabilities
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Metrics epss

{'score': 0.00035}

epss

{'score': 0.00056}

Weaknesses
  • CWE-319

    Cleartext Transmission of Sensitive Information

Sources

Status
PUBLISHED
Assigner
hackerone
Published
Updated
Oct 14, 2026, 6:26 PM
Reserved
Oct 20, 2022, 12:00 AM
Status
Modified
Published
Dec 23, 2022, 3:15 PM
Modified
Oct 14, 2026, 7:16 PM
Severity
Moderate
Public date
Dec 21, 2022, 12:00 AM