CVE-2026-55787
Flyto2 Core: SSRF guard bypass via IPv6 transition addresses (IPv4-mapped / 6to4 / NAT64) in validate_url_ssrf
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
Description
Flyto2 Core is an execution kernel for automation and AI-agent workflows. Prior to 2.26.3, validate_url_ssrf and is_private_ip in src/core/utils.py compare resolved addresses only against native private IPv4 and IPv6 ranges and do not unwrap IPv4-mapped, IPv4-compatible, 6to4, or NAT64 transition addresses. An authenticated workflow author can provide a transition-form literal URL through the Execution API POST /v1/execute route, http.get, or sibling guarded outbound-request modules, causing the guard to accept an address whose embedded IPv4 points to loopback, RFC 1918, or cloud metadata services. On a host that routes the selected transition form, the outbound request reaches the internal destination and returns the response body to the workflow caller, enabling read SSRF and disclosure of internal-service data or cloud credentials. This issue is fixed in version 2.26.3.
Public exploit
A reference of the record is tagged as an exploit or proof of concept: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: a proof of concept is public.
- https://github.com/flytohub/flyto-core/security/advisories/GHSA-794r-5rp2-fpg8 (opens in a new tab)x_refsource_CONFIRMexploit
Timeline
ID reserved
By GitHub_M
- 4 months later
· 4 months later
Published
- 1 day later
· 1 day later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | High7.1 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N |
| NVDNVD · Deferred | 3.1 | High7.1 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.29% · top 78% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.1.
Weakness
Affected products
- affected < 2.26.3
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- PyPIflyto-coreGHSA-794r-5rp2-fpg8 (opens in a new tab)
References (4)
- https://github.com/flytohub/flyto-core/security/advisories/GHSA-794r-5rp2-fpg8 (opens in a new tab)x_refsource_CONFIRMexploit
- https://github.com/flytohub/flyto-core/pull/20 (opens in a new tab)x_refsource_MISC
- https://github.com/flytohub/flyto-core/commit/519e040384a74984848c4e84a6600e5f1020a6d2 (opens in a new tab)x_refsource_MISC
- https://github.com/flytohub/flyto-core/releases/tag/v2.26.3 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-794r-5rp2-fpg8 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-55787)Record last updated .