# CVE-2021-22897: Information disclosure in https://github.com/curl/curl

> Concurrent transfers in curl using Schannel may share cipher settings, potentially weakening transport security and exposing data.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Jun 2021
- **Updated:** 14 Oct 2026
- **Also known as:** AZL-6358, CURL-CVE-2021-22897, ECHO-59c1-8ea7-4c79, GHSA-frcg-47mh-pj2g, JLSEC-2026-1333

## What is CVE-2021-22897?

CVE-2021-22897 is a medium-severity vulnerability in Haxx Curl, published on 11 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

curl 7.61.0 through 7.76.1 suffers from exposure of data element to wrong session due to a mistake in the code for CURLOPT_SSL_CIPHER_LIST when libcurl is built to use the Schannel TLS library. The selected cipher set was stored in a single "static" variable in the library, which has the surprising side-effect that if an application sets up multiple concurrent transfers, the last one that sets the ciphers will accidentally control the set used by all transfers. In a worst-case scenario, this weakens transport security significantly.

Weakness: CWE-668 (Exposure of Resource to Wrong Sphere), CWE-840

## Which versions are affected by CVE-2021-22897?

It affects 22 products.


Products: Haxx Curl, Netapp Cloud Backup, Netapp H300e Firmware, Netapp H300s Firmware, Netapp H410s Firmware, Netapp H500e Firmware, Netapp H500s Firmware, Netapp H700e Firmware, Netapp H700s Firmware, Netapp Hci Compute Node Firmware, Netapp Solidfire\, Enterprise Sds \& Hci Storage Node, Netapp Solidfire \& Hci Management Node, Netapp Solidfire Baseboard Management Controller Firmware, Oracle Communications Cloud Native Core Binding Support Function, Oracle Communications Cloud Native Core Network Function Cloud Native Environment, Oracle Communications Cloud Native Core Network Repository Function, Oracle Communications Cloud Native Core Network Slice Selection Function, Oracle Communications Cloud Native Core Service Communication Proxy, Oracle Essbase, Oracle Mysql Server and 2 more.

## How do I fix CVE-2021-22897?

Upgrade to a fixed version.

## Is CVE-2021-22897 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-22897 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-2021-22897 and fix it if it is affected.

What it is: CVE-2021-22897 is a medium-severity vulnerability in Haxx Curl, published on 11 Jun 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-2021-22897 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-2021-22897/ (Markdown: https://insights.sbomify.com/CVE-2021-22897/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-22897
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-22897
- OSV: https://osv.dev/vulnerability/CVE-2021-22897

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-22897/
Summaries are generated and may contain mistakes; the official description above is the record.