CVE-2026-11586 WS Auto-PONG memory exhaustion

What is CVE-2026-11586?

CVE-2026-11586 is a high-severity denial of service vulnerability in Haxx Curl, published on 3 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

By default, curl automatically responds to WebSocket PING frames. Because curl lacks an upper bound on memory allocation for unacknowledged frames, a malicious server can exhaust all available memory by flooding curl with rapid, sequential PING messages.

Weakness: CWE-770

Which versions are affected by CVE-2026-11586?

It affects 1 product.

Products include Haxx Curl.

How do I fix CVE-2026-11586?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-11586 being exploited?

There is no known exploitation of CVE-2026-11586 in the wild and no public exploit code.

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-2026-11586, BELL-CVE-2026-11586, CURL-CVE-2026-11586, DEBIAN-CVE-2026-11586, ECHO-2414-0950-1cdc, GHSA-c68q-h477-5646 and 4 more.