If you use an affected Fedify release, update now. Two vulnerabilities have been fixed in @fedify/fedify: CVE-2026-77632, a high-severity server-side request forgery vulnerability in the authenticated document loader, and CVE-2026-69132, a medium-severity denial-of-service vulnerability in the outbound delivery circuit breaker.

CVE-2026-77632 affects versions 1.6.1 through 2.3.4. Fedify uses an authenticated document loader when it fetches remote documents such as actors and public keys with a signed HTTP request. Affected versions checked that the initial URL was public, but did not apply the same check when that URL returned an HTTP redirect. An attacker who controlled the public URL could redirect the signed request to a loopback address, a link-local metadata service, or an RFC 1918 host. In the ordinary inbox path, Fedify may fetch a signature's keyId before it can verify the signature, so a bogus signature is enough to reach this path. The demonstrated attack is blind SSRF: the internal response is consumed while resolving the remote document and is not automatically returned to the attacker.

The fix validates every redirect target before it is fetched. The existing allowPrivateAddress option still permits private destinations when an application explicitly opts in, such as for a closed federation or test environment.

CVE-2026-69132 affects versions 2.3.0 through 2.3.4. Fedify 2.3 introduced an outbound delivery circuit breaker that records failures in the configured key–value store, using the remote inbox's host:port as part of the key. An attacker could send signed Follow activities from actors whose inbox URLs pointed to distinct ports where delivery would fail. Each failure created a separate record, allowing the attacker to grow circuit-breaker state until storage or memory was exhausted. Versions 2.3.0 and 2.3.1 were vulnerable with every circuit-breaker configuration. In versions 2.3.2 through 2.3.4, the vulnerable configuration was a custom failure policy without an explicit stateTtl.

The fix gives custom failure policies a bounded default stateTtl, equal to recoveryDelay plus heldActivityTtl (7 days 30 minutes with the default values). On stores that support compare-and-set operations, Fedify also sweeps circuit-breaker state left by affected releases and stamps it with a TTL. Applications that need a different retention period for a custom failure policy can continue to set stateTtl explicitly.

The SSRF fix first appeared in 2.0.25, 2.1.21, 2.2.10, and 2.3.5; the circuit-breaker fix first appeared in 2.3.5. The current releases on those lines are 2.0.26, 2.1.22, 2.2.11, and 2.3.6, and those are the versions we recommend installing. The circuit-breaker issue only affects the 2.3 line; the authenticated document-loader issue affects every Fedify release from 1.6.1 through 2.3.4. If you still use Fedify 1.x, change your dependency to a current 2.x release because package-manager update commands do not cross the declared major-version range.

The GitHub Security Advisories are GHSA-cxc3-7q96-6cpx and GHSA-fx98-wc5v-jrg5.

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 Jace and @nyanrus for the reports and responsible disclosure.

If anything is unclear, ask below.