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CVE-2026-54637: Dragonfly scheduler v1 gRPC unauthenticated SSRF via attacker-controlled PeerHost in DownloadTinyFile

• Severity: medium (CVSS 5.5 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-15 · updated 2026-09-30
• Weakness: CWE-918

Description

Dragonfly is an open source P2P-based file distribution and image acceleration system. Prior to 2.4.4-rc.3, the scheduler's default unauthenticated v1 gRPC flow accepts attacker-controlled PeerHost.Ip and PeerHost.DownPort values through RegisterPeerTask and ReportPeerResult, storeHost copies those values into resource.Host, and handlePeerSuccess invokes Peer.DownloadTinyFile() for a TINY task. DownloadTinyFile() in scheduler/resource/standard/peer.go builds an HTTP GET request from the supplied address without destination validation, allowing a remote attacker to probe loopback, link-local, and private services and place up to TinyFileSize, 128 bytes, of a response in Task.DirectPiece for later retrieval. PeerHost.DownPort is restricted to ports 1024 through 65534, and the issue provides read SSRF rather than remote code execution. The remediation blocks loopback and link-local targets, while RFC1918 destinations remain reachable because IsGlobalUnicast accepts private ranges. This issue is fixed in 2.4.4-rc.3.

Affected products

• dragonflyoss dragonfly: before 2.4.4-rc.3

References

• https://github.com/dragonflyoss/dragonfly/commit/4f9bd93d22453e3f433f9d912bfeeca22760c237
• https://github.com/dragonflyoss/dragonfly/releases/tag/v2.4.4-rc.3
• https://github.com/dragonflyoss/dragonfly/security/advisories/GHSA-chwm-m7g7-685g
• https://github.com/dragonflyoss/dragonfly/security/advisories/GHSA-chwm-m7g7-685g

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