---
title: "CVE-2026-67426: Flyto2 Core: Unauthenticated flyto-verification /run: callback_url SSRF and internal runner-secret exfiltration"
url: https://erroneo.us/security/cve/CVE-2026-67426/
description: "CVE-2026-67426 (flyto-core (PyPI)): Flyto2 Core is an execution kernel for automation and AI-agent workflows. Prior to 2.26.7, the standalone…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-07-29
date_modified: 2026-08-10
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-67426"
kev: false
cvss: 9.3
epss: 0.00507
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-67426: Flyto2 Core: Unauthenticated flyto-verification /run: callback_url SSRF and internal runner-secret exfiltration

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.5% , percentile 42: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 42% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes flyto-core (PyPI) >= 2.26.6, < 2.26.7, fixed in 2.26.7 . Check your lockfile, including transitive dependencies.

## What it is

Flyto2 Core is an execution kernel for automation and AI-agent workflows. Prior to 2.26.7, the standalone flyto-verification service in src/core/verificationservice.py exposes unauthenticated POST /run on 0.0.0.0:8344 and uses client-supplied callbackurl for an outbound POST with X-Internal-Key: $FLYTORUNNERSECRET while bypassing targetallowed, allowing unauthenticated SSRF and runner secret exfiltration. This issue is fixed in version 2.26.7.

## Affected packages

- PyPI `flyto-core` >= 2.26.6, < 2.26.7 → fixed: 2.26.7

## Affected products (CVE record)

- flytohub flyto-core: < 2.26.7

## Severity

- GitHub_M CVSS 3.1: 9.3 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N`
- GitHub CVSS 3.1: 9.3 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable yes , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 0.51% probability of exploitation activity in the next 30 days; percentile 42.

## Sources

- [GitHub Advisory GHSA-jx74-cqjv-2c67](https://github.com/advisories/GHSA-jx74-cqjv-2c67)
- [CVE.org record CVE-2026-67426](https://www.cve.org/CVERecord?id=CVE-2026-67426)
- [NVD entry CVE-2026-67426](https://nvd.nist.gov/vuln/detail/CVE-2026-67426)
- [github.com](https://github.com/flytohub/flyto-core/security/advisories/GHSA-jx74-cqjv-2c67)
- [github.com](https://github.com/flytohub/flyto-core/commit/0a0a528520ec18f5a21f1ddf858a71cc1edfb6e9)
- [github.com](https://github.com/flytohub/flyto-core/releases/tag/v2.26.7)
- [github.com](https://github.com/pypa/advisory-database/tree/main/vulns/flyto-core/PYSEC-2026-3571.yaml)

---
Source page: https://erroneo.us/security/cve/CVE-2026-67426/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt