Dragonfly scheduler v1 and v2 gRPC unauthenticated SSRF via attacker-controlled PeerHost in DownloadTinyFile

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

5.5 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P · score source

EPSS

• CVE-2026-54637: 0.80% estimated exploitation activity in the next 30 days; percentile 56.62 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary The Dragonfly scheduler's v1 gRPC service contains an unauthenticated Server-Side Request Forgery (SSRF). When a peer reports a successful download of a TINY task, the scheduler calls Peer.DownloadTinyFile() and issues an HTTP GET to a host and port taken verbatim from the attacker-controlled PeerHost.Ip / PeerHost.DownPort fields of the gRPC request body. The HTTP client uses a bare http.Transport with no address validation, so a remote, unauthenticated client can force the scheduler to connect to arbitrary internal addresses, including 127.0.0.1 (loopback), 169.254.0.0/16 (link-local, e.g. cloud metadata), and RFC1918 ranges. The fetched response is stored in Task.DirectPiece and can subsequently be served to other peers, making this a read-SSRF with a data-exfiltration path. The manager's preheat code path already wraps its HTTP client with nethttp.NewSafeDialer() (which rejects non-global-unicast destinations); the scheduler's DownloadTinyFile path is missing this guard…

Published by the source

6 Jul 2026, 20:32 UTC

Last modified by the source

6 Jul 2026, 20:57 UTC

Source last checked

26 Oct 2026, 15:24 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-chwm-m7g7-685g

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# Patch Next advisory brief: CVE-2026-54637

Advisory: Dragonfly scheduler v1 and v2 gRPC unauthenticated SSRF via attacker-controlled PeerHost in DownloadTinyFile
IDs: CVE-2026-54637, GHSA-chwm-m7g7-685g
Record: https://patchnext.com/advisories/cve-2026-54637 (revision 1, source checked 26 Oct 2026, 15:24 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: d7y.io/dragonfly/v2 2.4.4-rc.3. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go d7y.io/dragonfly/v2: affected <= 2.4.4-rc.2; fixed in 2.4.4-rc.3

## Suggested inspection (read-only)
- Go d7y.io/dragonfly/v2: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on d7y.io/dragonfly/v2.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-chwm-m7g7-685g (GitHub-reviewed advisory GHSA-chwm-m7g7-685g lists affected ranges: Go d7y.io/dragonfly/v2 >=0 <=2.4.4-rc.2)

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