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CVE-2026-100355low3.1

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

Impact

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 IPAddrprivate?  IPAddrloopback?, and IPAddrlink_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…

Source excerpt · GitHub_M

Affected packages

This source has no supported package-version data for matching. You can read the advisory here, but this record alone cannot power a dependency check.

Affected products

Vendor version evidence. Product records are separate from automatic dependency matching.

basecamp · GitHub_M

once-campfire

1 range
GitHub_M version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

< 1.4.5

unaffected

unknown

Other versions: unknown

Original source 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.

Inside the record

Evidence available

Package identity · not supplied
Version evidence
Remediation guidance · not supplied
Weakness classification
Additional publishers · not supplied

Describes the evidence in this view, not whether the product is safe.

Original records

CVE-2026-100355

View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.

cve.new JSON →

Underlying weaknesses

The source’s classification of what caused the vulnerability.

CWE-918 ↗

CWE-918: Server-Side Request Forgery (SSRF)

GitHub_M

Related →
Contributing organizations · 1
GitHub_M

Assigning organization

2026-10-30

What changed

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Large field values are marked as truncated previews. Original source snapshots remain retained.

References

4 sources
github.com/basecamp/once-campfire/security/advisories/GHSA-gjm7-g266-w3wj
Security advisoryGitHub_M
github.com/basecamp/once-campfire/pull/225
PatchGitHub_M
github.com/basecamp/once-campfire/commit/69e8cd788593cf421c32626a5273c0b449ceee9b
PatchGitHub_M
github.com/basecamp/once-campfire/releases/tag/v1.4.5
Release notesGitHub_M