CVE-2022-35260

.netrc parser out-of-bounds access

Project curl Security Advisory, October 26 2022 - Permalink

VULNERABILITY

curl can be told to parse a .netrc file for credentials. If that file ends in a line with consecutive non-white space letters and no newline, curl could read past the end of the stack-based buffer, and if the read works, write a zero byte possibly beyond its boundary.

This will in most cases cause a segfault or similar, but circumstances might also cause different outcomes.

If a malicious user can provide a custom netrc file to an application or otherwise affect its contents, this flaw could be used as denial-of-service.

INFO

The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2022-35260 to this issue.

CWE-121: Stack-based Buffer Overflow

Severity: low

AFFECTED VERSIONS

• Affected versions: curl 7.84.0 to and including 7.85.0
• Not affected versions: curl < 7.84.0 and >= 7.86.0
• Introduced-in: https://github.com/curl/curl/commit/eeaae10c0fb27aa06

libcurl is used by many applications, but not always advertised as such!

SOLUTION

• Fixed-in: https://github.com/curl/curl/commit/c97ec984fb2bc919a3aa86

RECOMMENDATIONS

A - Upgrade curl to version 7.86.0

B - Apply the patch to your local version

C - Do not use .netrc files

TIMELINE

This issue was reported to the curl project on October 3, 2022. We contacted distros@openwall on October 18, 2022.

libcurl 7.86.0 was released on October 26 2022, coordinated with the publication of this advisory.

CREDITS

• Reported-by: Hiroki Kurosawa
• Patched-by: Daniel Stenberg

Thanks a lot!