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CURL-CVE-2012-0036

Published Jan 24, 2012·Last modified Apr 25, 2026
Affected Components(0)

No affected components available

Description

curl is vulnerable to a data injection attack for certain protocols through control characters embedded or percent-encoded in URLs.

When parsing URLs, libcurl's parser is liberal and only parses as little as possible and lets as much as possible through as long as it can figure out what to do.

In the specific process when libcurl extracts the file path part from a given URL, it did not always verify the data or escape control characters properly before it passed the file path on to the protocol-specific code that then would use it for its protocol business.

This passing through of control characters could be exploited by someone who would be able to pass in a handcrafted URL to libcurl. Lots of libcurl using applications let users enter URLs in one form or another and not all of these check the input carefully to prevent malicious ones.

A malicious user might pass in %0d%0a to get treated as CR LF by libcurl, and by using this fact a user can trick for example a POP3 client to delete a message instead of getting it or trick an SMTP server to send an unintended message.

This vulnerability can be used to fool libcurl with the following protocols: IMAP, POP3 and SMTP.

Both curl the command line tool and applications using the libcurl library are vulnerable.

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
N/A

Probability that this vulnerability will be exploited in the wild within the next 30 days.

Exploit
Not available

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

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