CVE-2026-87866
Received
Received - Intake
curl TLS Certificate Validation Bypass with wolfSSL
Vulnerability report for CVE-2026-87866, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-10-20
Last updated on: 2026-10-20
Assigner: curl
Description
Description
When built with wolfSSL, curl can successfully validate a pinned public key
hash against a key the TLS peer does not possess. During the TLS handshake,
wolfSSL validates the connection, but curl's subsequent re-parsing of the same
certificate - tricked by a manipulated validity length field - extracts and
matches a different embedded key, incorrectly authorizing the pinned public
key.
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| curl | curl | 8.22.0 |
| curl | curl | 8.21.0 |
| curl | curl | 8.20.0 |
| curl | curl | 8.19.0 |
| curl | curl | 8.18.0 |
| curl | curl | 8.17.0 |
| curl | curl | 8.16.0 |
| curl | curl | 8.15.0 |
| curl | curl | 8.14.1 |
| curl | curl | 8.14.0 |
| curl | curl | 8.13.0 |
| curl | curl | 8.12.1 |
| curl | curl | 8.12.0 |
| curl | curl | 8.11.1 |
| curl | curl | 8.11.0 |
| curl | curl | 8.10.1 |
| curl | curl | 8.10.0 |
| curl | curl | 8.9.1 |
| curl | curl | 8.9.0 |
| curl | curl | 8.8.0 |
| curl | curl | 8.7.1 |
| curl | curl | 8.7.0 |
| curl | curl | 8.6.0 |
| curl | curl | 8.5.0 |
| curl | curl | 8.4.0 |
| curl | curl | 8.3.0 |
| curl | curl | 8.2.1 |
| curl | curl | 8.2.0 |
| curl | curl | 8.1.2 |
| curl | curl | 8.1.1 |
| curl | curl | 8.1.0 |
| curl | curl | 8.0.1 |
| curl | curl | 8.0.0 |
| curl | curl | 7.88.1 |
| curl | curl | 7.88.0 |
| curl | curl | 7.87.0 |
| curl | curl | 7.86.0 |
| curl | curl | 7.85.0 |
| curl | curl | 7.84.0 |
| curl | curl | 7.83.1 |
| curl | curl | 7.83.0 |
| curl | curl | 7.82.0 |
| curl | curl | 7.81.0 |
| curl | curl | 7.80.0 |
| curl | curl | 7.79.1 |
| curl | curl | 7.79.0 |
| curl | curl | 7.78.0 |
| curl | curl | 7.77.0 |
| curl | curl | 7.76.1 |
| curl | curl | 7.76.0 |
| curl | curl | 7.75.0 |
| curl | curl | 7.74.0 |
| curl | curl | 7.73.0 |
| curl | curl | 7.72.0 |
| curl | curl | 7.71.1 |
| curl | curl | 7.71.0 |
| curl | curl | 7.70.0 |
| curl | curl | 7.69.1 |
| curl | curl | 7.69.0 |
| curl | curl | 7.68.0 |
| curl | curl | 7.67.0 |
| curl | curl | 7.66.0 |
| curl | curl | 7.65.3 |
| curl | curl | 7.65.2 |
| curl | curl | 7.65.1 |
| curl | curl | 7.65.0 |
| curl | curl | 7.64.1 |
| curl | curl | 7.64.0 |
| curl | curl | 7.63.0 |
| curl | curl | 7.62.0 |
| curl | curl | 7.61.1 |
| curl | curl | 7.61.0 |
| curl | curl | 7.60.0 |
| curl | curl | 7.59.0 |
| curl | curl | 7.58.0 |
| curl | curl | 7.57.0 |
| curl | curl | 7.56.1 |
| curl | curl | 7.56.0 |
| curl | curl | 7.55.1 |
| curl | curl | 7.55.0 |
| curl | curl | 7.54.1 |
| curl | curl | 7.54.0 |
| curl | curl | 7.53.1 |
| curl | curl | 7.53.0 |
| curl | curl | 7.52.1 |
| curl | curl | 7.52.0 |
| curl | curl | 7.51.0 |
| curl | curl | 7.50.3 |
| curl | curl | 7.50.2 |
| curl | curl | 7.50.1 |
| curl | curl | 7.50.0 |
| curl | curl | 7.49.1 |
| curl | curl | 7.49.0 |
| curl | curl | 7.48.0 |
| curl | curl | 7.47.1 |
| curl | curl | 7.47.0 |
| curl | curl | 7.46.0 |
| curl | curl | 7.45.0 |
| curl | curl | 7.44.0 |
| curl | curl | 7.43.0 |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
