# CVE-2021-22926: Security feature bypass in https://github.com/curl/curl

> Attackers can trick libcurl into using a malicious certificate file if the application runs in a writable directory, bypassing intended TLS authentication.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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:** 5 Aug 2021
- **Updated:** 14 Oct 2026
- **Also known as:** ALPINE-CVE-2021-22926, AZL-6364, CURL-CVE-2021-22926, ECHO-c377-ec84-0da8, GHSA-5xph-62q2-pxff, JLSEC-2026-1338

## What is CVE-2021-22926?

CVE-2021-22926 is a high-severity vulnerability in Haxx Curl, published on 5 Aug 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

libcurl-using applications can ask for a specific client certificate to be used in a transfer. This is done with the `CURLOPT_SSLCERT` option (`--cert` with the command line tool).When libcurl is built to use the macOS native TLS library Secure Transport, an application can ask for the client certificate by name or with a file name - using the same option. If the name exists as a file, it will be used instead of by name.If the appliction runs with a current working directory that is writable by other users (like `/tmp`), a malicious user can create a file name with the same name as the app wants to use by name, and thereby trick the application to use the file based cert instead of the one referred to by name making libcurl send the wrong client certificate in the TLS connection handshake.

Weakness: CWE-295 (Improper Certificate Validation), CWE-840

## Which versions are affected by CVE-2021-22926?

It affects 19 products.


Products: Haxx Curl, Netapp Active Iq Unified Manager, Netapp Clustered Data Ontap, Netapp H300e Firmware, Netapp H300s Firmware, Netapp H410s Firmware, Netapp H500e Firmware, Netapp H500s Firmware, Netapp H700e Firmware, Netapp H700s Firmware, Netapp Hci Management Node, Netapp Oncommand Insight, Netapp Oncommand Workflow Automation, Netapp Snapcenter, Netapp Solidfire, Oracle Mysql Server, Oracle Peoplesoft Enterprise Peopletools, Siemens Sinec Infrastructure Network Services, Splunk Universal Forwarder.

## How do I fix CVE-2021-22926?

Apply the vendor's patch.

## Is CVE-2021-22926 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-22926 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-2026-10536](https://insights.sbomify.com/CVE-2026-10536/): HTTP/2 stream-dependency tree UAF (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)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-22926 and fix it if it is affected.

What it is: CVE-2021-22926 is a high-severity vulnerability in Haxx Curl, published on 5 Aug 2021. 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-2021-22926 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-2021-22926/ (Markdown: https://insights.sbomify.com/CVE-2021-22926/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-22926
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-22926
- OSV: https://osv.dev/vulnerability/CVE-2021-22926

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-22926/
Summaries are generated and may contain mistakes; the official description above is the record.