# CVE-2026-9080: curl libcurl use-after-free in CURLMOPT_SOCKETFUNCTION callback

Source: https://junglewise.ai/threats/cve-2026-9080-curl-libcurl-use-after-free-in-curlmopt-socketfunction-callback  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-03. Updated: 2026-07-03  
License: CC BY 4.0 with a link back

CVE-2026-9080 · Severity: info · CVSS 0 · Published 2026-07-03

A vulnerability exists in libcurl, a widely used library for transferring data over various network protocols. When an application using libcurl pauses a transfer during a specific internal event, the library may attempt to access memory that has already been released. This could lead to application crashes or potentially allow for unauthorized code execution, though the curl command-line tool itself is not affected.

## Quick answers

**Is CVE-2026-9080 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-9080 being exploited in the wild.

**How severe is CVE-2026-9080?** Informational severity, with a CVSS score of 0, published 3 July 2026.

**Which products and versions are affected?** curl curl 8.13.0 to 8.20.0.

**Is there a fix for CVE-2026-9080?** A patch was published on 2026-06-24: Fixed in curl version 8.21.0 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-9080 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-9080?** Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A use-after-free (UAF) vulnerability (CWE-416) exists in libcurl versions 8.13.0 through 8.20.0. The flaw is triggered when an application calls `curl_easy_pause()` from within the event-based `CURLMOPT_SOCKETFUNCTION` callback. In this scenario, libcurl attempts to store a flag using a dangling struct pointer immediately after that pointer's memory has been freed. While the curl command-line tool is unaffected, library users are at risk of memory corruption. The issue is fixed in version 8.21.0.

## Affected products

- curl curl 8.13.0 to 8.20.0

## Timeline

- 2026-05-19: disclosed: Reported to the curl project
- 2026-06-24: patched: Fixed in curl version 8.21.0
- 2026-06-24: advisory: Project curl security advisory published
- 2026-07-03: other: CVE record published to NVD

## References

- [https://curl.se/docs/CVE-2026-9080.html](https://curl.se/docs/CVE-2026-9080.html)
- [https://curl.se/docs/CVE-2026-9080.json](https://curl.se/docs/CVE-2026-9080.json)
- [https://hackerone.com/reports/3749204](https://hackerone.com/reports/3749204)