An issue was discovered in Squid 2.x through 2.7.STABLE9, 3.x through 3.5.28, and 4.x through 4.7. When Squid is configured to use Basic Authentication, the Proxy-Authorization header is parsed via uudecode. uudecode determines how many bytes will be decoded by iterating over the input and checking its table. The length is then used to start decoding the string. There are no checks to ensure that the length it calculates isn't greater than the input buffer. This leads to adjacent memory being decoded as well. An attacker would not be able to retrieve the decoded data unless the Squid maintainer had configured the display of usernames on error pages.
Created squid tracking bugs for this issue:
Affects: fedora-all [bug 1730529]
Remove 'auth_param basic ...' configuration settings from squid.conf
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):
This issue has been addressed in the following products:
Red Hat Enterprise Linux 8
Via RHSA-2020:4743 https://access.redhat.com/errata/RHSA-2020:4743