If you use Fedify, update to a patched release now. CVE-2026-62857 affects Fedify's NodeInfo client. An attacker who runs any instance your server looks up could cause that server to fetch non-public network destinations and return their contents to your application, depending on the deployment environment and network routing.
Fedify can look up a remote instance's NodeInfo document to learn what software it runs. The lookup happens in two steps: it fetches the instance's /.well-known/nodeinfo document, then follows the NodeInfo document URL that response advertises. The vulnerable path is getNodeInfo(), along with the Context.lookupNodeInfo() method that wraps it: affected versions sent both requests without validating the destination against public-network expectations. Because that second URL comes straight out of the remote server's response body, the instance being looked up fully controls it, and could point it at a loopback address, a link-local metadata endpoint, an RFC 1918 host, or a data: URL. Servers are exposed only if they look up NodeInfo, but that lookup is routine for peer discovery and instance metadata.
The fix routes both requests through the same public-address validation Fedify already applied to WebFinger lookups and remote document loading. Every request is now checked before it is sent, including each redirect hop, so a public URL cannot bounce a request to an internal address. Redirects are followed with a cap and are refused if they cross protocols, and non-HTTP(S) URLs such as data: are rejected outright.
These are patch releases, so they tighten behavior without adding new API. If you deliberately look up NodeInfo on a private or intranet address, such as in a closed federation or a test environment, these releases will now refuse it. An allowPrivateAddress opt-out is coming in 2.4.0.
Current patched releases are 1.9.13, 1.10.12, 2.0.22, 2.1.18, 2.2.7, and 2.3.2. The GitHub Security Advisory is GHSA-hqph-j65v-8cq5, and the CVE ID is CVE-2026-62857.
Update @fedify/fedify:
npm update @fedify/fedify
yarn upgrade @fedify/fedify
pnpm update @fedify/fedify
bun update @fedify/fedify
deno update @fedify/fedify
After updating, redeploy. If you run other Fedify-based servers, update those too.
Thanks to @rvzsec and @manus-use for the report and responsible disclosure.
If anything is unclear, ask below.
