{"cve":"CVE-2026-91987","nvd":{"published":"2026-09-15T16:17:57.300","modified":"2026-09-24T20:48:01.433","status":"Deferred","description":"atomic-agents-stack before 1.1.0 contains a cost-guardrail bypass in the _estimate_batch_cost function that returns zero cost for unknown models not in the pricing table. Attackers can configure deployments with unknown model identifiers to bypass daily cost caps and exceed budget limits in parallel batch operations.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","score":7.1},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":6.5},"cwes":["CWE-770"],"references":["https://github.com/dep0we/atomic-agents-stack/security/advisories/GHSA-j659-8xh6-5pq5","https://www.vulncheck.com/advisories/atomic-agents-stack-before-1.1.0-cost-guardrail-bypass-via-unknown-model"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:53:43.293028046+00:00"},"epss":{"cve":"CVE-2026-91987","score":0.00476,"percentile":0.41149,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-j659-8xh6-5pq5","url":"https://osv.dev/vulnerability/GHSA-j659-8xh6-5pq5","summary":"atomic-agents-stack: Parallel helper/delegate batch reserves $0 for models absent from the pricing table, bypassing the cost-cap fan-out guard","modified":"2026-09-16T03:56:06.072717965Z","packages":[{"ecosystem":"PyPI","name":"atomic-agents-stack","purl":"pkg:pypi/atomic-agents-stack","ranges":["<1.1.0"],"fixed":["1.1.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}