CVE-2026-91988
CVE-2026-91988
atomic-agents-stack before 1.1.0 accepts cleartext HTTP schemes in the HTTP MCP server-registry backend factory, allowing network man-in-the-middle attackers to rewrite catalog responses. Attackers can inject arbitrary command and argument values that are spawned as local subprocesses by MCPClientPool to achieve code execution on the agent host.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.003 (24.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 25th percentile — 24.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Weakness classification (CWE)
References
- github.com/dep0we/atomic-agents-stack/security/advisories/GHSA-xhcr-cqfr-m3hv (vendor-advisory)
- www.vulncheck.com/advisories/atomic-agents-stack-before-1.1.0-remote-code-execu… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-91988?
- CVE-2026-91988 is a high-severity vulnerability, classified under Cleartext Transmission of Sensitive Information. CVSS score: 8.1/10. Published 2026-09-15.
- How severe is CVE-2026-91988?
- High severity. CVSS v3 base score is 8.1 out of 10.