CVE-2026-103956
CRITICAL 10 DETECTION TEMPLATEMissing authentication for critical function in the authentication dependency in Loom for AWS before 1.6.1 allowed remote actors to obtain super-admin authority over the agent control plane, including registering tool servers, reading stored integration credentials, and rewriting the IAM role policies attached to managed agent roles, via any request to the application API in a deployment where no identity provider is configured. To remediate this issue, users should upgrade to version 1.6.1 or later.
Severe if exploited (CVSS 10), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
2.5%chance of exploitation in 30 days · 85th percentile
Impact if exploited
10CVSS 4.0 · CRITICAL
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityHigh
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ✓Privileges: No account or privileges required
- ✓User interaction: No user interaction needed
- ✓Complexity: No special conditions — reliably repeatable
- ✓Requirements: No special attack requirements
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept
No public PoC is currently catalogued.
Detection templates
Detection checks are listed separately from PoCs.
Resource commands
nuclei -id CVE-2026-103956 -u https://TARGETDetection template — review its checks and affected versions before use.Search for new PoCs
Search GitHub now — results may be empty or unverified.
Tracked sources are checked daily for recent CVEs, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.
Data snapshot:
Weakness (CWE)
- CWE-306: Missing authentication for critical function
- CWE-1188: Initialization of a resource with an insecure default
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
References and research data (JSON)
Unverified PoC candidates
Catalogue matches for further research. These repositories have not been validated as working exploits.
1 candidate
- https://github.com/abraxas/cve-2026-103956-loom-unauth
CVE-2026-103956 - Loom for AWS - Critical - Auth bypass - unauthenticated super-admin when no IdP is configured
PoC-in-GitHub · CVE-2026-103956
PoC-in-GitHub · CVE-2026-103956 · Updated 2026-10-14T13:21:25Z
All CVSS metrics
- CRITICAL 10 v3.1 · CNA Primary
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H - CRITICAL 10 v4.0 · CNA Primary
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H - CRITICAL 10 v4.0 · NVD Secondary
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CRITICAL 10 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
References
Patches & mitigations
- https://github.com/awslabs/loom/releases/tag/v1.6.1 CVE record · AMZN · Updated 2026-10-09T16:36:18.246Z
NVD · CVE-2026-103956 · Updated 2026-10-06T14:49:40.823
Advisories
- https://aws.amazon.com/security/security-bulletins/2026-124-aws/ CVE record · AMZN · Updated 2026-10-09T16:36:18.246Z
NVD · CVE-2026-103956 · Updated 2026-10-06T14:49:40.823 - https://github.com/awslabs/loom/security/advisories/GHSA-vgmj-998f-r8mp CVE record · AMZN · Updated 2026-10-09T16:36:18.246Z
NVD · CVE-2026-103956 · Updated 2026-10-06T14:49:40.823 - https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-91770 EUVD · EUVD-2026-91770