CVE-2017-1000254 Memory corruption in n/a

What is CVE-2017-1000254?

CVE-2017-1000254 is a high-severity memory corruption vulnerability in Haxx Libcurl, published on 6 Oct 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

libcurl may read outside of a heap allocated buffer when doing FTP. When libcurl connects to an FTP server and successfully logs in (anonymous or not), it asks the server for the current directory with the `PWD` command. The server then responds with a 257 response containing the path, inside double quotes. The returned path name is then kept by libcurl for subsequent uses. Due to a flaw in the string parser for this directory name, a directory name passed like this but without a closing double quote would lead to libcurl not adding a trailing NUL byte to the buffer holding the name. When libcurl would then later access the string, it could read beyond the allocated heap buffer and crash or wrongly access data beyond the buffer, thinking it was part of the path. A malicious server could abuse this fact and effectively prevent libcurl-based clients to work with it - the PWD command is always issued on new FTP connections and the mistake has a high chance of causing a segfault. The simple fact that this has issue remained undiscovered for this long could suggest that malformed PWD responses are rare in benign servers. We are not aware of any exploit of this flaw. This bug was introduced in commit [415d2e7cb7](https://github.com/curl/curl/commit/415d2e7cb7), March 2005. In libcurl version 7.56.0, the parser always zero terminates the string but also rejects it if not terminated properly with a final double quote.

Weakness: CWE-119

Which versions are affected by CVE-2017-1000254?

It affects 1 product.

Products include Haxx Libcurl.

How do I fix CVE-2017-1000254?

Upgrade to a fixed version.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2017-1000254 being exploited?

There is no known exploitation of CVE-2017-1000254 in the wild and no public exploit code.

Other vulnerabilities in Haxx Libcurl

• CVE-2024-6197 freeing stack buffer in utf8asn1str High 7.5
• CVE-2016-7141 Auth bypass in n/a High 7.5
• CVE-2017-1000099 Information disclosure in n/a Medium 6.5
• CVE-2017-1000100 Information disclosure in n/a Medium 6.5
• CVE-2024-7264 ASN.1 date parser overread Medium 6.3

All Haxx Libcurl vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as ALPINE-CVE-2017-1000254, CURL-CVE-2017-1000254, DEBIAN-CVE-2017-1000254, DLA-1121-1, GHSA-499v-2pwm-c696, SUSE-SU-2017:2789-1 and 2 more.