{"id":"CVE-2026-67428","aliases":["GHSA-pgwh-4jj4-qm8v","PYSEC-2026-3572"],"url":"https://o3.security/vulnerability/CVE-2026-67428","summary":"Flyto2 Core: Multiple HTTP-family modules fetch client-controlled URLs without the SSRF guard their siblings apply (SSRF to internal/metadata)","details":"## Summary\nNumerous HTTP-emitting modules (`core.api.http_get`, `core.api.http_post`, `graphql.query`/`graphql.mutation`, `monitor.http_check`, `communication.slack_send`, `notification.{discord,slack,teams}.send_message`, `ai.vision_analyze` [anthropic path], `verify.visual_diff`, `browser.proxy_rotate`, and the `agent`/`llm` inline base_url branch) perform outbound requests to a fully client-controlled URL **without calling the project's own SSRF guard** (`validate_url_with_env_config`) that their sibling modules apply. An authenticated workflow-author can point the URL at the cloud metadata IP (169.254.169.254), a loopback/RFC1918 host, or any internal host and read the response, yielding cloud-metadata credential theft and internal service read/write.\n\n## Root Cause\nThe SSRF guard is per-module (there is NO global egress interception). Each module must call `validate_url_with_env_config` before issuing a request. The listed modules never call it — they only carry an `ssrf_protected` **metadata tag string** which enforces nothing. Exemplar: `src/core/modules/third_party/developer/http/requests.py` — grepping for `validate_url|ssrf|is_private` in requests.py returns 0 guard calls; `session.get(url)` fires at `:85` (HTTPGetModule) and `session.post` at `:188` (HTTPPostModule). SECURITY.md incorrectly lists `api.http_get` as SSRF-protected.\n\n## Impact\nReadable SSRF: full `{status_code, headers, body}` returned to the caller (requests.py:96-108). Enables theft of cloud IAM credentials from the metadata endpoint and read/write access to internal-only APIs. Scope Changed (S:C) — the request crosses into cloud-metadata / internal-network authority the workflow layer does not otherwise have.\n\n## Proof of Concept\nVerified live this session: `core.api.http_get` with `url` pointed at a loopback internal server returned the internal body `INTERNAL-SECRET-IAM-CREDENTIALS`, while the guarded sibling `http.get` returned `NETWORK_ERROR: Hostname blocked: 127.0.0.1` on the same input — proving the branch-asymmetry is real (not a port artifact).\n```\nPOST /mcp {\"method\":\"tools/call\",\"params\":{\"name\":\"execute_module\",\n  \"arguments\":{\"module_id\":\"core.api.http_get\",\n  \"params\":{\"url\":\"http://<cloud-metadata-ip>/latest/meta-data/iam/security-credentials/\"}}}}\n```\n\n## Attack Chain\n1. Entry: authenticated MCP client → `POST /mcp` execute_module `core.api.http_get`, url set to the cloud metadata endpoint. Guard: `require_auth` (mcp.py:71). Bypass proof: passes with a valid workflow-author bearer token (PR:L).\n2. Check: capability denylist / `enforce_module_policy` (base.py:240). Bypass proof: `core.api.*` not in `_DEFAULT_DENYLIST` (module_policy.py:45-67) → `is_allowed=True` (runtime-registration verified: `core.api.http_get -> HTTPGetModule`).\n3. Check: SSRF validation. Bypass proof: `requests.py` has ZERO `validate_url`/ssrf calls — only the `ssrf_protected` tag string at :23/:116. `session.get(url)` fires at :85.\n4. Sink: aiohttp GET/POST to the cloud metadata IP.\n5. Impact: full response body returned → IAM credential theft, internal read/write.\n\n## Bypass Evidence\nGrepping `validate_url|ssrf|is_private` in requests.py → 0 guard calls (2 hits are both the inert tag string). Live PoC returned internal body directly; guarded sibling blocked the same input. Direct IP works — no IPv6 transition trick needed (AC:L), unlike the seed CVE-2026-55787.\n\n## Affected Versions\n`<= 2.26.6` — code present on latest release tag v2.26.6 (`requests.py:19,112`).\n\n## Suggested Fix\nCall `validate_url_with_env_config(url)` in each listed module before issuing the outbound request, matching the guarded siblings (e.g. `ai.model:157`, `http.get`). Best: route all outbound HTTP through a single guarded client wrapper so new modules inherit the guard.\n\n## Credit\n\nVulnerability discovered by zx (Jace).","published":"2026-07-29T18:48:42.087Z","modified":"2026-10-28T02:30:58.978689146Z","cvss":{"score":8.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N"},"epss":{"score":0.00337,"percentile":0.26979,"asOf":"2026-09-16"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"flyto-core","fixedVersion":"2.26.7"}],"fix":{"url":"https://github.com/flytohub/flyto-core/commit/0a0a528520ec18f5a21f1ddf858a71cc1edfb6e9","label":"flytohub/flyto-core@0a0a528"},"references":[{"type":"WEB","url":"https://github.com/flytohub/flyto-core/releases/tag/v2.26.7"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/67xxx/CVE-2026-67428.json"},{"type":"ADVISORY","url":"https://github.com/flytohub/flyto-core/security/advisories/GHSA-pgwh-4jj4-qm8v"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-67428"},{"type":"FIX","url":"https://github.com/flytohub/flyto-core/commit/0a0a528520ec18f5a21f1ddf858a71cc1edfb6e9"},{"type":"PACKAGE","url":"https://github.com/flytohub/flyto-core"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-28T02:30:58.978689146Z"}}