Unauthenticated internal service access via unfiltered CGNAT addresses
Published Aug 24, 2026 · Updated Aug 24, 2026
SSRF in BentoML 1.4.19 through 1.4.39 allows remote attackers to reach CGNAT-hosted internal services through crafted request URLs. make_safe_connect rejects private, loopback, and link-local addresses but passes RFC 6598 addresses because Python does not classify 100.64.0.0/10 under those properties. An exposed service accepting URL-backed multipart or JSON inputs is sufficient to trigger outbound requests that probe or read reachable internal services.
Summary
What happened
SSRF in BentoML 1.4.19 through 1.4.39 allows remote attackers to reach CGNAT-hosted internal services through crafted request URLs. make_safe_connect rejects private, loopback, and link-local addresses but passes RFC 6598 addresses because Python does not classify 100.64.0.0/10 under those properties. An exposed service accepting URL-backed multipart or JSON inputs is sufficient to trigger outbound requests that probe or read reachable internal services.
The record
- CVE
- CVE-2026-78205
- Published
- Aug 24, 2026
- Updated
- Aug 24, 2026
- Vendor
- BentoML
- Product
- BentoML
- Classifications
- CWE-918, T1046, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 24, 2026CVE publishedPublication date reported by the CVE source.
- Aug 24, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=1.4.19 <=1.4.39
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- GitHub Issue #5644 CGNAT SSRF PoCproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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