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.
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Fixes

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History

Fri, 30 Oct 2026 14:15:00 +0000

Type Values Removed Values Added
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.
Title Campfire vulnerable to SSRF via incomplete private-network denylist in the link-unfurl guard
Weaknesses CWE-918
References
Metrics cvssV3_1

{'score': 3.1, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-30T14:10:34.695Z

Reserved: 2026-09-25T19:19:54.697Z

Link: CVE-2026-100355

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-30T14:16:35.690

Modified: 2026-10-30T14:16:35.690

Link: CVE-2026-100355

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-30T15:30:16Z

Weaknesses