CVE-2026-9545

CVE Enrichment

CVSS: 7.5 HIGH
EPSS: 0.41%
EPSS Percentile: 33.14%
CISA KEV: Not listed

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uses a proper HTTP/3 server for the initial transfers, and when it makes a second transfer to the same site it has been replaced by the attacker's impostor machine - without a valid certificate.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.

Technical Details

CVSS Version: 3.1
CNA / NVD Source: 2499f714-1537-4658-8207-48ae4bb9eae9
Published: 03-Jul-2026 14:16
Last Modified: 15-Sep-2026 14:16
EPSS Date: 2026-10-12
CWE: CWE-200

CVSS Vector


            CVSS:3.1                            AV:N /
                            AC:L /
                            PR:N /
                            UI:N /
                            S:U /
                            C:H /
                            I:N /
                            A:N

Affected Products / Versions

haxx / curl
Version / affected range: * · from (inclusive) 8.11.0 · before (exclusive) 8.21.0
cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*

References

Last enrichment sync: 12-Oct-2026 23:57
Sources: NVD · FIRST EPSS · CISA KEV
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Reported Context (1)

Since the reports are at different stages of that process, only subsets are publicly disclosed today, such as curl’s CVE-2026-9545 and CVE-2026-13608, Node.js’s CVE-2026-56848, and Linux kernel CVE-2026-64563. Microsoft FORGE Shares Lessons from AI-Assisted Vulnerability Research at Scale

CVE (3)

People (1)

Vendors (1)

Products (4)

Tools (3)

Note: Related entities, including threat actors, malware, CVEs, MITRE ATT&CK techniques, vendors, products, tools, countries, and industries, are shown when they appear in the same reporting. Their presence does not necessarily mean they were targeted, compromised, vulnerable, responsible for the activity, or directly involved in the incident.