CVE-2025-32792 — ses
CVE-2025-32792 is a CWE-497 vulnerability in ses. A fix is available for ses — see the affected versions and patch details below.
ses's global contour bindings leak into Compartment lexical scope
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-32792.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
sesnpmDescription
Impact
Web pages and web extensions using ses and the Compartment API to evaluate third-party code in an isolated execution environment that have also elsewhere used const, let, and class bindings in the top-level scope of a <script> tag will have inadvertently revealed these bindings in the lexical scope of third-party code.
Patches
This compromise is addressed in ses version 1.12.0. The mechanism for confining third-party code involves a with block and a semi-opaque scope Proxy. The proxy previously revealed any named property to the surrounding lexical scope if it were absent on globalThis, so that the third-party code would receive an informative ReferenceError, relying on the invalid assumption that only properties of globalThis are in the top-level lexical scope. The solution makes the scope proxy fully opaque. Consequently, accessing an unbound free lexical name will produce undefined instead of throwing ReferenceError.
Assigning to an unbound free lexical name will continue to throw a ReferenceError.
Workarounds
This problem can be mitigated either by avoiding top-level let, const, or class bindings in <script> tags, which is an existing industry best-practice, or change these to var bindings to be reflected on globalThis, or upgrade ses to version 1.12.0 or greater.
Some bundlers by default transform top-level let, const, and class bindings to var.
Disclosure
This vulnerability was disclosed by @mingijunggrape in the course of their studies at UNIST (Ulsan National Institute of Science and Technology) as a member of the Web Security Lab (https://websec-lab.github.io/).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | ses | all versions | 1.12.0npm install ses@1.12.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ses, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update ses to 1.12.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-32792 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is CVE-2025-32792 in your dependencies?
Find it across npm, including transitive dependencies.