# CVE-2023-23915: Security feature bypass in https://github.com/curl/curl

> Attackers can bypass HSTS protection in curl when parallel transfers overwrite the cache, allowing insecure HTTP connections.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/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:** 23 Feb 2023
- **Updated:** 14 Oct 2026
- **Also known as:** ALPINE-CVE-2023-23915, AZL-13649, AZL-13652, AZL-13655, AZL-13660, AZL-34601, AZL-38093, CLEANSTART-2026-NK66737, CURL-CVE-2023-23915, DEBIAN-CVE-2023-23915, ECHO-a7e9-9bbf-4f58, GHSA-2c3h-vr56-625m, JLSEC-2026-403, ROOT-OS-DEBIAN-11-CVE-2023-23915, UBUNTU-CVE-2023-23915

## What is CVE-2023-23915?

CVE-2023-23915 is a medium-severity vulnerability in Haxx Curl, published on 23 Feb 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A cleartext transmission of sensitive information vulnerability exists in curl <v7.88.0 that could cause HSTS functionality to behave incorrectly when multiple URLs are requested in parallel. Using its HSTS support, curl can be instructed to use HTTPS instead of using an insecure clear-text HTTP step even when HTTP is provided in the URL. This HSTS mechanism would however surprisingly fail when multiple transfers are done in parallel as the HSTS cache file gets overwritten by the most recentlycompleted transfer. A later HTTP-only transfer to the earlier host name would then *not* get upgraded properly to HSTS.

Weakness: CWE-319 (Cleartext Transmission of Sensitive Information)

## Which versions are affected by CVE-2023-23915?

It affects 8 products.


Products: Haxx Curl, Netapp Active Iq Unified Manager, Netapp Clustered Data Ontap, Netapp H300s Firmware, Netapp H410s Firmware, Netapp H500s Firmware, Netapp H700s Firmware, Splunk Universal Forwarder.

## How do I fix CVE-2023-23915?

Upgrade to a fixed version.

## Is CVE-2023-23915 being exploited?

There is no known exploitation of CVE-2023-23915 in the wild and no public exploit code.

## 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-2023-23915 and fix it if it is affected.

What it is: CVE-2023-23915 is a medium-severity vulnerability in Haxx Curl, published on 23 Feb 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-23915 in the wild and no public exploit code.

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-2023-23915/ (Markdown: https://insights.sbomify.com/CVE-2023-23915/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-23915
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-23915
- OSV: https://osv.dev/vulnerability/CVE-2023-23915

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-23915/
Summaries are generated and may contain mistakes; the official description above is the record.