CVE-2026-9545

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Source
https://cve.org/CVERecord?id=CVE-2026-9545
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-9545.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2026-9545
Aliases
Downstream
Related
Published
2026-07-03T06:17:55.931Z
Modified
2026-07-11T18:29:54.114949293Z
Severity
  • 7.5 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N CVSS Calculator
Summary
exposing HTTP/3 early data
Details

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uses a proper HTTP/3 server for the initial transfers, and when it makes a second transfer to the same site it has been replaced by the attacker's impostor machine - without a valid certificate.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

Database specific 
{
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/9xxx/CVE-2026-9545.json",
    "unresolved_ranges": [
        {
            "source": "AFFECTED_FIELD",
            "extracted_events": [
                {
                    "introduced": "8.20.0"
                },
                {
                    "last_affected": "8.20.0"
                },
                {
                    "introduced": "8.19.0"
                },
                {
                    "last_affected": "8.19.0"
                },
                {
                    "introduced": "8.18.0"
                },
                {
                    "last_affected": "8.18.0"
                },
                {
                    "introduced": "8.17.0"
                },
                {
                    "last_affected": "8.17.0"
                },
                {
                    "introduced": "8.16.0"
                },
                {
                    "last_affected": "8.16.0"
                },
                {
                    "introduced": "8.15.0"
                },
                {
                    "last_affected": "8.15.0"
                },
                {
                    "introduced": "8.14.1"
                },
                {
                    "last_affected": "8.14.1"
                },
                {
                    "introduced": "8.14.0"
                },
                {
                    "last_affected": "8.14.0"
                },
                {
                    "introduced": "8.13.0"
                },
                {
                    "last_affected": "8.13.0"
                },
                {
                    "introduced": "8.12.1"
                },
                {
                    "last_affected": "8.12.1"
                },
                {
                    "introduced": "8.12.0"
                },
                {
                    "last_affected": "8.12.0"
                },
                {
                    "introduced": "8.11.1"
                },
                {
                    "last_affected": "8.11.1"
                },
                {
                    "introduced": "8.11.0"
                },
                {
                    "last_affected": "8.11.0"
                }
            ]
        }
    ],
    "cna_assigner": "curl"
}
References

Affected packages

Git / github.com/curl/curl

Affected ranges

Type
GIT
Repo
https://github.com/curl/curl
Events
Introduced
b1ef0e1a01c0bb6ee5367bd9c186a603bde3615a
Fixed
68720b4837284335b2d63cb358f8f6ce65f5bc55
Database specific 
{
    "source": "CPE_RANGE",
    "cpe": "cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*",
    "extracted_events": [
        {
            "introduced": "8.11.0"
        },
        {
            "fixed": "8.21.0"
        }
    ]
}

Affected versions

Other
curl-8_11_0
curl-8_11_1
curl-8_12_0
curl-8_12_1
curl-8_13_0
curl-8_14_0
curl-8_14_1
curl-8_15_0
curl-8_16_0
curl-8_17_0
curl-8_18_0
curl-8_19_0
curl-8_20_0
rc-8_20_0-1
rc-8_20_0-2
rc-8_20_0-3
rc-8_21_0-1
rc-8_21_0-2
rc-8_21_0-3

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-9545.json"