CVE-2026-9545
7.5 · HIGHOverview
CVE-2026-9545 is a high-severity vulnerability affecting haxx curl. It was published on July 3, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
In this scenario, libcurl first uses a proper HTTP/3 server for the initial
transfers, and when it makes a second transfer to the same site it has been
replaced by the attacker's impostor machine - without a valid certificate.
When libcurl returns to the hostname the second time with a cached SSL session
(`CURLOPT_SSL_SESSIONID_CACHE` is not disabled) and early data enabled (the
`CURLSSLOPT_EARLYDATA` bit is set in `CURLOPT_SSL_OPTIONS`), libcurl might
send off the second request's bytes on that new connection *before* enforcing
the certificate verification failure. Potentially leaking sensitive
information.
Remediation
Check the references section for vendor advisories and patches from haxx. Update curl to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| haxx | curl | >= 8.11.0, < 8.21.0 | Affected |
Frequently Asked Questions
What is CVE-2026-9545?
CVE-2026-9545 is a high-severity vulnerability affecting haxx curl. It was published on July 3, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).
How severe is CVE-2026-9545?
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-9545?
Check the references section for vendor advisories and patches from haxx. Update curl to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-9545?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-9545 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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