Bugzilla – Bug 1199222
VUL-0: CVE-2022-27780: curl: percent-encoded path separator in URL host (3/6)
Last modified: 2022-09-16 12:52:43 UTC
percent-encoded path separator in URL host
Project curl Security Advisory, May 11 2022 -
The curl URL parser wrongly accepts percent-encoded URL separators like '/'
when decoding the host name part of a URL, making it a *different* URL using
the wrong host name when it is later retrieved.
For example, a URL like `http://example.com%2F10.0.0.1/`, would be allowed by
the parser and get transposed into `http://example.com/10.0.0.1/`. This flaw
can be used to circumvent filters, checks and more.
We are not aware of any exploit of this flaw.
This flaw was introduced in [commit
in curl 7.80.0 when curl added support for percent-encoded host names in URLs.
The Common Vulnerabilities and Exposures (CVE) project has assigned the name
CVE-2022-27780 to this issue.
CWE-177: Improper Handling of URL Encoding
- Affected versions: curl 7.80.0 to and including 7.83.0
- Not affected versions: curl < 7.83.0 and curl >= 7.83.1
libcurl is used by many applications, but not always advertised as such!
The URL parser now rejects host names that percent-decode into URL separator
A [fix for CVE-2022-27780](https://github.com/curl/curl/commit/914aaab9153764e)
A - Upgrade curl to version 7.83.1
B - Apply the patch to your local version
This issue was reported to the curl project on April 28, 2022. We contacted
distros@openwall on May 5.
libcurl 7.83.1 was released on May 11 2022, coordinated with the publication
of this advisory.
This issue was reported by Axel Chong. Patched by Daniel Stenberg.
Thanks a lot!
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Everything was done. Sent it back to security team.