Quick answers
- Is CVE-2026-123562 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-123562 being exploited in the wild.
- How severe is CVE-2026-123562?
- High severity, with a CVSS score of 7.5, published 8 November 2026.
- Which products and versions are affected?
- Sveltejs Devalue 5.8.0 to 5.9.2.
- Is there a fix for CVE-2026-123562?
- Yes: fixed in 5.9.3. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-123562 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-123562?
- Check whether you run Sveltejs Devalue at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- Fixed in: 5.9.3
Technical details
When stringifyAsync serializes multiple promises, a later promise rejecting before an earlier one settles can leave an internal rejection unhandled even if the caller catches the returned promise. This is a CWE-248 (uncaught exception) issue; under Node's default unhandled-rejection behavior, the process terminates. The attack requires ability to influence the timing or failure of serialized asynchronous values.
Affected products
- sveltejs devalue 5.8.0 to 5.9.2
Timeline
- 2026-09-18: disclosed
- 2026-11-08: advisory