Open-Source Security Intelligence

Know every vulnerability
before it knows you.

DevGuard continuously monitors your dependencies and alerts you when CVEs like this one affect your stack — with real-time threat intelligence built for developers.

Search

CURL-CVE-2016-8617

Published Nov 2, 2016·Last modified Apr 25, 2026
Affected Components(0)

No affected components available

Description

In libcurl's base64 encode function, the output buffer is allocated as follows without any checks on insize:

malloc( insize * 4 / 3 + 4 )

On systems with 32-bit addresses in userspace (e.g. x86, ARM, x32), the multiplication in the expression wraps around if insize is at least 1GB of data. If this happens, an undersized output buffer is allocated, but the full result is written, thus causing the memory behind the output buffer to be overwritten.

If a username is set directly via CURLOPT_USERNAME (or curl's -u, --user option), this vulnerability can be triggered. The name has to be at least 512MB big in a 32-bit system.

Systems with 64-bit versions of the size_t type are not affected by this issue.

Risk Scores
Base Score
0.0

Measures severity based on intrinsic characteristics of the vulnerability, independent of environment.

Threat Intelligence
0.0

No exploitation activity has been observed at this time. Continue routine monitoring.

EPSS
0.59%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

Scan your project

Continuously monitor your dependencies and get alerted when vulnerabilities like this one affect your stack.

Checkout DevGuard