Raw 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/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:XCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-103956 is a critical-severity Missing Authentication for Critical Function (CWE-306) vulnerability in Amazon (inferred from references). Its CVSS base score is 10.0 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Valid Accounts (T1078); ranked at the 39th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to AC-14 (Permitted Actions Without Identification or Authentication) and AC-3 (Access Enforcement) — see the control section below for these in your framework.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-91770
Vulnerability Data
Missing 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…
more
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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 17 hardening rules · 7 OS baselines
V14.3.2V6.3.2V11.3.1V13.2.3
Mitigating Controls (NIST 800-53 r5) AI
Explicitly identifies and limits actions permitted without authentication, preventing critical functions from being exposed.
Access enforcement requires prior authentication before any authorization decision for critical functions.
Least privilege reduces the blast radius of any insecure default permissions that remain after initialization.
Baseline configuration directly requires documenting and maintaining secure initial settings instead of insecure defaults.
Configuration settings mandate the most restrictive values be applied at initialization, eliminating reliance on insecure factory defaults.
Directly mandates unique identification and authentication of users before access to functions requiring identity.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Pre-acquisition integrity checks can reject products known to ship with insecure defaults.
Managing identities and credentials is a prerequisite for authentication but does not itself enforce it on critical functions.
Directly requires authentication of users/services/hardware, which eliminates missing authentication for critical functions.
Defining and enforcing authorizations assumes prior authentication and therefore only partially mitigates the absence of authentication.
Protecting networks from unauthorized access can be undermined by missing authentication but does not address the root authentication gap.
Hardened baselines and configuration management directly replace insecure defaults with secure settings.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Mandating authentication requirements for critical functions at the requirements-gathering stage ensures that essential operations are not left unprotected by missing login or verification mechanisms.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (higher-evidence rows only; rows rated `none` are excluded).
Oracle Linux 8 (3 rules)
- V-248585 OL 8 must require reauthentication when using the "sudo" command. blocks CWE-306
- V-248823 OL 8 must not have the telnet-server package installed. blocks CWE-1188
- V-248827 OL 8 must not have the rsh-server package installed. blocks CWE-306
RHEL 7 (3 rules)
- V-204627 SNMP community strings on the Red Hat Enterprise Linux operating system must be changed from the default. blocks CWE-1188
- V-204442 The Red Hat Enterprise Linux operating system must not have the rsh-server package installed. blocks CWE-306
- V-237635 The Red Hat Enterprise Linux operating system must require re-authentication when using the "sudo" command. blocks CWE-306
RHEL 8 (2 rules)
- V-230492 RHEL 8 must not have the rsh-server package installed. blocks CWE-306
- V-237643 RHEL 8 must require re-authentication when using the "sudo" command. blocks CWE-306
Ubuntu 22.04 (1 rule)
- V-260529 Ubuntu 22.04 LTS must be configured so that remote X connections are disabled, unless to fulfill documented and validated mission requirements. blocks CWE-1188
Ubuntu 24.04 (1 rule)
- V-270708 Ubuntu 24.04 LTS must be configured so that remote X connections are disabled, unless to fulfill documented and validated mission requirements. blocks CWE-1188
Windows Server 2016 (1 rule)
- V-224972 Active Directory Group Policy objects must have proper access control permissions. blocks CWE-1188
Windows Server 2019 (1 rule)
- V-205741 Windows Server 2019 Active Directory Group Policy objects must have proper access control permissions. blocks CWE-1188