# 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.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 3 Jul 2026
- **Updated:** 15 Sep 2026
- **Also known as:** ALPINE-CVE-2026-10536, AZL-91818, AZL-91839, BELL-CVE-2026-10536, CURL-CVE-2026-10536, DEBIAN-CVE-2026-10536, ECHO-0d6f-7fbe-c7fa, GHSA-wjq8-x4qm-6mmh, JLSEC-2026-1197, MINI-vgm9-vx39-f32r, MINI-x888-fhwf-c2pr, ROOT-OS-ALPINE-315-CVE-2026-10536, ROOT-OS-ALPINE-320-CVE-2026-10536, ROOT-OS-ALPINE-321-CVE-2026-10536, ROOT-OS-ALPINE-322-CVE-2026-10536, ROOT-OS-DEBIAN-12-CVE-2026-10536, ROOT-OS-DEBIAN-13-CVE-2026-10536, UBUNTU-CVE-2026-10536

## 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 (Use After Free)

## Which versions are affected by CVE-2026-10536?

It affects 1 product.


Products: Haxx Curl.

## How do I fix CVE-2026-10536?

Upgrade to a fixed version.

## 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

- [CVE-2026-19931](https://insights.sbomify.com/CVE-2026-19931/): Negotiate ambient user conn reuse (critical 9.8)
- [CVE-2026-11856](https://insights.sbomify.com/CVE-2026-11856/): cross-origin Digest auth state leak (critical 9.8)
- [CVE-2026-8925](https://insights.sbomify.com/CVE-2026-8925/): SASL double-free (critical 9.8)
- [CVE-2026-9079](https://insights.sbomify.com/CVE-2026-9079/): stale proxy password leak (critical 9.8)
- [CVE-2016-4606](https://insights.sbomify.com/CVE-2016-4606/): Code injection in curl (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-10536 and fix it if it is affected.

What it is: 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.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-10536 exists.

Affected product: Haxx Curl. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-10536/ (Markdown: https://insights.sbomify.com/CVE-2026-10536/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-10536
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-10536
- OSV: https://osv.dev/vulnerability/CVE-2026-10536

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-10536/
Summaries are generated and may contain mistakes; the official description above is the record.