High 7.1Published Oct 14, 2026

CVE-2026-55787Flyto2 Core: SSRF guard bypass via IPv6 transition addresses (IPv4-mapped / 6to4 / NAT64) in validate_url_ssrf

Updated under an hour ago (2026-10-19 10:10 UTC)

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It affects flytohub flyto-core. Add what you run to find out whether that includes you.

EPSS puts the chance of exploitation in the next 30 days at 0.24%, higher than 14% of scored CVEs.

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Exploited in the last 30 days

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.

CVSS: 7.1 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N
Weakness (CWE): CWE-918
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): 0.24% (percentile 14)
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Oct 15, 2026
First seen by InfoSec Signals: Oct 14, 2026

Affected products

Affected products

flytohub flyto-core flytohub:flyto_core (from the name)	before 2.26.3	CNA record

References

https://github.com/flytohub/flyto-core/security/advisories/GHSA-794r-5rp2-fpg8x-refsource-confirm
https://github.com/flytohub/flyto-core/pull/20x-refsource-misc
https://github.com/flytohub/flyto-core/commit/519e040384a74984848c4e84a6600e5f1020a6d2x-refsource-misc
https://github.com/flytohub/flyto-core/releases/tag/v2.26.3x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.