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CVE-2026-100355EUVD-2026-114058

Campfire vulnerable to SSRF via incomplete private-network denylist in the link-unfurl guard

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 1.4.5
None on Exploit-DB, Metasploit or GitHub

Summary

Campfire, a web-based chat application, is affected by a server-side request forgery flaw in its link preview feature, which fetches links posted in messages. The flaw lets an authenticated user reach internal network resources through certain special-use address ranges, potentially exposing limited metadata from those internal services.

Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.

Read the original description

Campfire is a web-based chat application. In version 1.4.4 and earlier, when a Campfire message contains a link, the server fetches it to build an OpenGraph unfurl preview. `RestrictedHTTP::PrivateNetworkGuard` relied on Ruby's `IPAddr#private? `` IPAddr#loopback?`, and `IPAddr#link_local?` predicates plus IPv4-mapped and IPv4-compatible checks, which do not cover several special-use ranges. An authenticated user can post a link to a hostname resolving to CGNAT `100.64.0.0/10`, NAT64 `64:ff9b::/96` or `64:ff9b:1::/48`, or 6to4 `2002::/16` to bypass the guard and cause server-side requests to internal network resources. The NAT64 and 6to4 ranges can embed an internal IPv4 target. Confidentiality impact is limited to returned OpenGraph metadata, and most internal endpoints return none. There is no integrity or availability impact. An initial fix was released in version 1.4.5.

Timeline

  1. CVE published
  2. First seen by cve.now

Affected versions

  • basecamp once-campfire

    fixed in 1.4.5

References 4

GitHub · basecamp/once-campfire