CVE-2019-1020001: Path Traversal
Possible arbitrary path traversal and file access via yard server
Impact
A path traversal vulnerability was discovered in YARD <= 0.9.19 when using yard server to serve documentation. This bug would allow unsanitized HTTP requests to access arbitrary files on the machine of a yard server host under certain conditions.
Thanks to CuongMX from Viettel Cyber Security for discovering this vulnerability.
Patches
Please upgrade to YARD v0.9.20 immediately if you are relying on yard server to host documentation in any untrusted environments.
Workarounds
For users who cannot upgrade, it is possible to perform path sanitization of HTTP requests at your webserver level. WEBrick, for example, can perform such sanitization by default (which you can use via yard server -s webrick), as can certain rules in your webserver configuration.
Other sources
yard before 0.9.20 allows path traversal.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2019-1020001?
CVE-2019-1020001 has a medium severity rating due to its potential impact on file access.
How do I fix CVE-2019-1020001?
To fix CVE-2019-1020001, upgrade to YARD version 0.9.20 or later.
Which versions of YARD are affected by CVE-2019-1020001?
YARD versions prior to 0.9.20 are affected by CVE-2019-1020001.
What type of vulnerability is CVE-2019-1020001?
CVE-2019-1020001 is a path traversal vulnerability that allows arbitrary file access.
How does CVE-2019-1020001 affect HTTP requests?
CVE-2019-1020001 allows unsanitized HTTP requests made to the yard server to access arbitrary files.