CVE-2020-8285
curl: Malicious FTP server can trigger stack overflow when CURLOPT_CHUNK_BGN_FUNCTION is used
Severity
ModerateRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · December 9, 2020
Updated · September 21, 2026
Description
Libcurl offers a wildcard matching functionality, which allows a callback (set with CURLOPT_CHUNK_BGN_FUNCTION) to return information back to libcurl on how to handle a specific entry in a directory when libcurl iterates over a list of all available entries. When this callback returns CURL_CHUNK_BGN_FUNC_SKIP, to tell libcurl to not deal with that file, the internal function in libcurl then calls itself recursively to handle the next directory entry. If there's a sufficient amount of file entries and if the callback returns "skip" enough number of times, libcurl runs out of stack space. The exact amount will of course vary with platforms, compilers and other environmental factors.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
CVSS / CWE
CVSS 3.1 · 6.5CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
CWE-835 · Loop with Unreachable Exit Condition ('Infinite Loop')