CVE-2026-91987

high

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.

References

https://www.vulncheck.com/advisories/atomic-agents-stack-before-1.1.0-cost-guardrail-bypass-via-unknown-model

https://github.com/dep0we/atomic-agents-stack/security/advisories/GHSA-j659-8xh6-5pq5

Details

Source: Mitre, NVD

Published: 2026-09-15

Updated: 2026-09-17

Risk Information

CVSS v2

Base Score: 6.8

Vector: CVSS2#AV:N/AC:L/Au:S/C:N/I:N/A:C

Severity: Medium

CVSS v3

Base Score: 6.5

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Severity: Medium

CVSS v4

Base Score: 7.1

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

Severity: High

EPSS

EPSS: 0.0037