How severe is CVE-2026-103956?

CVE-2026-103956 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-103956 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-103956?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-103956 published?

CVE-2026-103956 was published on 2026-10-02 and last updated on 2026-10-06.

CVE-2026-103956

CVE-2026-103956 is a critical-severity vulnerability with a CVSS 3.x base score of 10.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-306.

Key facts

Severity: Critical (CVSS 3.x base score 10.0)
CVSS v4: 10.0
EPSS exploit prediction: 0% (38th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-306
Published: 2026-10-02
Last modified: 2026-10-06

Description

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 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.

Frequently asked questions

What is CVE-2026-103956?: 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 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.
How severe is CVE-2026-103956?: CVE-2026-103956 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-103956 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (38th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-103956?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-103956 published?: CVE-2026-103956 was published on 2026-10-02 and last updated on 2026-10-06.

References

Other CWE-306 (Missing Authentication for Critical Function) vulnerabilities

CVE-2026-63692 — Critical (CVSS 10.0): Dell Container Storage Modules, versions prior to 1.18.0, contain(s) a Missing Authentication for Critical Function…
CVE-2026-63688 — Critical (CVSS 10.0): Dell Container Storage Modules (CSM), versions prior to v1.18.0, contains a Missing Authentication for Critical…
CVE-2026-53988 — Critical (CVSS 10.0): Dockhand before 1.0.40 contains an authentication bypass vulnerability in its git webhook endpoints that allows…
CVE-2026-85889 — Critical (CVSS 10.0): Missing authentication for critical function in Azure AI Foundry allows an unauthorized attacker to elevate privileges…
CVE-2026-92808 — Critical (CVSS 10.0): A server-side request forgery (SSRF) vulnerability exists in the UnifiedLogin service of Altium Enterprise Server. An…
CVE-2026-59971 — Critical (CVSS 10.0): MySQL MCP Server is a Model Context Protocol server that enables secure interaction with MySQL databases. Prior to…

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