FreshPorts - VuXML

cURL project reports:

libcurl is vulnerable to a case of missing out the checking of the certificate CN or SAN name field when the digital signature verification is turned off.

libcurl offers two separate and independent options for verifying a server's TLS certificate. CURLOPT_SSL_VERIFYPEER and CURLOPT_SSL_VERIFYHOST. The first one tells libcurl to verify the trust chain using a CA cert bundle, while the second tells libcurl to make sure that the name fields in the server certificate meets the criteria. Both options are enabled by default.

This flaw had the effect that when an application disabled CURLOPT_SSL_VERIFYPEER, libcurl mistakenly also skipped the CURLOPT_SSL_VERIFYHOST check. Applications can disable CURLOPT_SSL_VERIFYPEER and still achieve security by doing the check on its own using other means.

The curl command line tool is not affected by this problem as it either enables both options or disables both at the same time.

>= 7.21.4 lt 7.33.0_2

cURL developers report:

libcurl is vulnerable to a case of bad checking of the input data which may lead to heap corruption.

The function curl_easy_unescape() decodes URL-encoded strings to raw binary data. URL-encoded octets are represented with %HH combinations where HH is a two-digit hexadecimal number. The decoded string is written to an allocated memory area that the function returns to the caller.

The function takes a source string and a length parameter, and if the length provided is 0 the function will instead use strlen() to figure out how much data to parse.

The "%HH" parser wrongly only considered the case where a zero byte would terminate the input. If a length-limited buffer was passed in which ended with a '%' character which was followed by two hexadecimal digits outside of the buffer libcurl was allowed to parse alas without a terminating zero, libcurl would still parse that sequence as well. The counter for remaining data to handle would then be decreased too much and wrap to become a very large integer and the copying would go on too long and the destination buffer that is allocated on the heap would get overwritten.

We consider it unlikely that programs allow user-provided strings unfiltered into this function. Also, only the not zero-terminated input string use case is affected by this flaw. Exploiting this flaw for gain is probably possible for specific circumstances but we consider the general risk for this to be low.

The curl command line tool is not affected by this problem as it doesn't use this function.

There are no known exploits available at this time.

>= 7.7 lt 7.24.0_4