CVE-2025-4947 QUIC certificate check skip with wolfSSL

What is CVE-2025-4947?

CVE-2025-4947 is a medium-severity vulnerability in Haxx Curl, published on 28 May 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

libcurl accidentally skips the certificate verification for QUIC connections when connecting to a host specified as an IP address in the URL. Therefore, it does not detect impostors or man-in-the-middle attacks.

Weakness: CWE-295

Which versions are affected by CVE-2025-4947?

It affects 1 product.

Products include Haxx Curl.

How do I fix CVE-2025-4947?

Upgrade to a fixed version.

Is CVE-2025-4947 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-4947 exists.

Other vulnerabilities in Haxx Curl

• CVE-2026-19931 Negotiate ambient user conn reuse Critical 9.8
• CVE-2026-10536 HTTP/2 stream-dependency tree UAF Critical 9.8
• CVE-2026-11856 cross-origin Digest auth state leak Critical 9.8
• CVE-2026-8925 SASL double-free Critical 9.8
• CVE-2026-9079 stale proxy password leak Critical 9.8

All Haxx Curl vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as ALPINE-CVE-2025-4947, AZL-62055, CLEANSTART-2026-FC20847, CURL-CVE-2025-4947, DEBIAN-CVE-2025-4947, ECHO-2ea7-6406-0262 and 3 more.