CVE-2026-10536 HTTP/2 stream-dependency tree UAF
A use-after-free in libcurl allows attackers to execute code or cause denial of service when specific HTTP/2 dependency options are used with handle resets.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-10536?
CVE-2026-10536 is a critical use after free 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
A use-after-free vulnerability exists in libcurl when an application configures an HTTP/2 stream-dependency tree via `CURLOPT_STREAM_DEPENDS` or `CURLOPT_STREAM_DEPENDS_E`, subsequently invokes `curl_easy_reset()`, and finally terminates the handle with `curl_easy_cleanup()`. During this final cleanup phase, libcurl attempts to access and modify an internal structure that was already freed during the reset operation.
Weakness: CWE-416
Which versions are affected by CVE-2026-10536?
It affects 1 product.
Products include Haxx Curl.
How do I fix CVE-2026-10536?
Upgrade to a fixed version.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-10536 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-10536 exists.
Other vulnerabilities in Haxx Curl
Sources
Also known as ALPINE-CVE-2026-10536, AZL-91818, AZL-91839, BELL-CVE-2026-10536, CURL-CVE-2026-10536, DEBIAN-CVE-2026-10536 and 12 more.