# CVE-2016-8622: Integer overflow in curl

> An integer overflow in libcurl's URL decoding can lead to heap buffer overflows, potentially allowing remote code execution or denial of service.

- **Severity:** Low 3.7 (`CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/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:** 31 Jul 2018
- **Updated:** 15 Apr 2026
- **Also known as:** ALPINE-CVE-2016-8622, CLEANSTART-2026-XZ19364, CURL-CVE-2016-8622, DEBIAN-CVE-2016-8622, GHSA-xfmx-53v5-938g, UBUNTU-CVE-2016-8622

## What is CVE-2016-8622?

CVE-2016-8622 is a low-severity vulnerability in Haxx Libcurl, published on 31 Jul 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The URL percent-encoding decode function in libcurl before 7.51.0 is called `curl_easy_unescape`. Internally, even if this function would be made to allocate a unscape destination buffer larger than 2GB, it would return that new length in a signed 32 bit integer variable, thus the length would get either just truncated or both truncated and turned negative. That could then lead to libcurl writing outside of its heap based buffer.

Weakness: CWE-787 (Out-of-bounds Write), CWE-190 (Integer Overflow or Wraparound), CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2016-8622?

It affects 1 product.


Products: Haxx Libcurl.

## How do I fix CVE-2016-8622?

Upgrade to a fixed version.

## Is CVE-2016-8622 being exploited?

There is no known exploitation of CVE-2016-8622 in the wild and no public exploit code.

## Other vulnerabilities in Haxx Libcurl

- [CVE-2024-6197](https://insights.sbomify.com/CVE-2024-6197/): freeing stack buffer in utf8asn1str (high 7.5)
- [CVE-2017-1000254](https://insights.sbomify.com/CVE-2017-1000254/): Memory corruption in n/a (high 7.5)
- [CVE-2016-7141](https://insights.sbomify.com/CVE-2016-7141/): Auth bypass in n/a (high 7.5)
- [CVE-2017-1000099](https://insights.sbomify.com/CVE-2017-1000099/): Information disclosure in n/a (medium 6.5)
- [CVE-2017-1000100](https://insights.sbomify.com/CVE-2017-1000100/): Information disclosure in n/a (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-8622 and fix it if it is affected.

What it is: CVE-2016-8622 is a low-severity vulnerability in Haxx Libcurl, published on 31 Jul 2018. 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-2016-8622 in the wild and no public exploit code.

Affected product: Haxx Libcurl. 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-2016-8622/ (Markdown: https://insights.sbomify.com/CVE-2016-8622/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-8622
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-8622
- OSV: https://osv.dev/vulnerability/CVE-2016-8622

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From sbomify Insights: https://insights.sbomify.com/CVE-2016-8622/
Summaries are generated and may contain mistakes; the official description above is the record.