{"items":[{"id":"NVI-00016296","kind":"vulnerability","title":"Crawl4AI: AST Sandbox Escape via gi_frame.f_back Chain - Pre-Auth RCE in Docker API","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-qxjp-w3pj-48m7","CVE-2026-53753"],"plain_summary":"GitHub lists this reviewed advisory for crawl4ai. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-64ac83b8ed07338bb59b2e5aae8f9271"],"action_type":"investigate","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[{"kind":"CVSS","as_of":"2026-07-20T21:11:45.000Z","value":"9.8 critical","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-64ac83b8ed07338bb59b2e5aae8f9271"}],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-64ac83b8ed07338bb59b2e5aae8f9271","url":"https://github.com/advisories/GHSA-qxjp-w3pj-48m7","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-qxjp-w3pj-48m7","publisher":"GitHub Advisory Database","observed_at":"2026-11-04T02:47:44.783Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-64ac83b8ed07338bb59b2e5aae8f9271"],"technology":"crawl4ai","known_exclusions":[],"conditions_summary":"### Summary\n\nThe `_safe_eval_expression()` function in the computed fields feature uses an AST validator that only blocks attributes starting with underscore. Python generator and frame object attributes (`gi_frame`, `f_back`, `f_builtins`) do NOT start with underscore, enabling a complete sandbox escape to achieve arbitrary code execution.\n\nThe attack requires no authentication (JWT disabled by default) and is triggered via `POST /crawl` with a crafted extraction schema.\n\n### Attack Vector\n\nAn attacker sends a `POST /crawl` request with a `JsonCssExtractionStrategy` schema containing a malicious computed field expression that:\n1. Creates a generator to access `gi_frame`\n2. Walks the frame chain via `f_back`\n3. Reaches `f_builtins` containing the real `__import__`\n4. Imports `os` and executes arbitrary commands\n\n### Impact\n\nUnauthenticated remote code execution inside the Docker container. An attacker can execute arbitrary system commands, read/write files, and exfiltrate secrets.\n\n### Fix Details\n\n1. Removed `eval()` from computed field expression path entirely -- expressions now log a warning and return default value\n2. Deleted `_safe_eval_expression()` function and `_SAFE_EVAL_B","public_affected_ranges":["<= 0.8.6"]}],"null_published_at":"2026-11-04T10:04:27.929Z","source_updated_at":"2026-07-20T21:11:45.000Z","source_disclosed_at":"2026-06-16T20:13:07.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"First indexed by Null; source disclosure date is shown separately.","null_first_observed_at":"2026-11-04T02:47:44.783Z"}],"next_cursor":null,"snapshot_revision":"42594"}