CVE-2023-39532

What it is

SES is a JavaScript environment that allows safe execution of arbitrary programs in Compartments. In version 0.18.0 prior to 0.18.7, 0.17.0 prior to 0.17.1, 0.16.0 prior to 0.16.1, 0.15.0 prior to 0.15.24, 0.14.0 prior to 0.14.5, an 0.13.0 prior to 0.13.5, there is a hole in the confinement of guest applications under SES that may manifest as either the ability to exfiltrate information or execute arbitrary code depending on the configuration and implementation of the surrounding host. Guest program running inside a Compartment with as few as no endowments can gain access to the surrounding host’s dynamic import by using dynamic import after the spread operator, like `{...import(arbitraryModuleSpecifier)}`. On the web or in web extensions, a Content-Security-Policy following ordinary best practices likely mitigates both the risk of exfiltration and execution of arbitrary code, at least limiting the modules that the attacker can import to those that are already part of the application. However, without a Content-Security-Policy, dynamic import can be used to issue HTTP requests for either communication through the URL or for the execution of code reachable from that origin. Within an XS worker, an attacker can use the host’s module system to the extent that the host has been configured. This typically only allows access to module code on the host’s file system and is of limited use to an attacker. Within Node.js, the attacker gains access to Node.js’s module system. Importing the powerful builtins is not useful except insofar as there are side-effects and tempered because dynamic import returns a promise. Spreading a promise into an object renders the promises useless. However, Node.js allows importing data URLs, so this is a clear path to arbitrary execution. Versions 0.18.7, 0.17.1, 0.16.1, 0.15.24, 0.14.5, and 0.13.5 contain a patch for this issue. Some workarounds are available. On the web, providing a suitably constrained Content-Security-Policy mitigates most of the threat. With XS, building a binary that lacks the ability to load modules at runtime mitigates the entirety of the threat. That will look like an implementation of `fxFindModule` in a file like `xsPlatform.c` that calls `fxRejectModuleFile`.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.

Exploit odds

1.3% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2023-08-08 17:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 06:12 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 1.3% in the next 30 days (EPSS).
• Severity: 9.8 CRITICAL (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2023-08-08 17:15 UTC

Last modified

2026-06-17 06:12 UTC

Exploit probability

1.3% · EPSS, next 30 days

Weakness

CWE-20 · Improper input validation

Record status

Modified

Affected

• Agoric Ses < 0.13.5
• Agoric Ses < 0.14.5
• Agoric Ses < 0.15.24
• Agoric Ses < 0.18.7
• Agoric Ses 0.16.0
• Agoric Ses 0.17.0

Attack profile CVSS 3.1 · 9.8

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Is it in your code?

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