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.
Metrics
Affected Vendors & Products
References
History
Fri, 06 Nov 2026 19:30:00 +0000
| Type | Values Removed | Values Added |
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| Metrics |
ssvc
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Fri, 30 Oct 2026 23:15:00 +0000
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| First Time appeared |
Basecamp
Basecamp once-campfire |
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| Vendors & Products |
Basecamp
Basecamp once-campfire |
Fri, 30 Oct 2026 14:15:00 +0000
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| 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 |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published: 2026-10-30T14:10:34.695Z
Updated: 2026-11-05T21:29:44.987Z
Reserved: 2026-09-25T19:19:54.697Z
Link: CVE-2026-100355
Updated: 2026-11-05T21:29:38.263Z
Status : Deferred
Published: 2026-10-30T14:16:35.690
Modified: 2026-11-05T22:17:41.653
Link: CVE-2026-100355
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