CVE-2026-8368: LWP::UserAgent versions before 6.83 for Perl leak Authorization and Proxy-Authorization headers on cross-origin redirects Stig Palmquist 12 May 2026 14:07 UTC

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CVE-2026-8368                                        CPAN Security Group
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        CVE ID:  CVE-2026-8368
  Distribution:  libwww-perl
      Versions:  before 6.83

      MetaCPAN:  https://metacpan.org/dist/libwww-perl
      VCS Repo:  https://github.com/libwww-perl/libwww-perl

LWP::UserAgent versions before 6.83 for Perl leak Authorization and
Proxy-Authorization headers on cross-origin redirects

Description
-----------
LWP::UserAgent versions before 6.83 for Perl leak Authorization and
Proxy-Authorization headers on cross-origin redirects.

On a 3xx response, the redirect handler strips only Host and Cookie
before issuing the follow-up request. Caller-supplied Authorization and
Proxy-Authorization headers are sent unchanged to the redirect target,
including across scheme, host, or port changes.

A redirect to an attacker controlled host therefore discloses the
caller's credentials to that host.

Problem types
-------------
- CWE-522 Insufficiently Protected Credentials

Solutions
---------
Upgrade to libwww-perl 6.83 or later.

References
----------
https://github.com/libwww-perl/libwww-perl/commit/9c4aeb6f2dd32f2b7eaf2d7827cade31ea6cb2c6.patch
https://metacpan.org/release/OALDERS/libwww-perl-6.83/changes
https://github.com/libwww-perl/libwww-perl/pull/512
https://github.com/libwww-perl/libwww-perl/pull/284

Timeline
--------
- 2026-05-11: Issue reported.
- 2026-05-12: libwww-perl 6.83 released with fix.

Credits
-------
Kai Aizen, reporter