# CVE-2026-27971: Qwik remote code execution via server$ deserialization

Source: https://junglewise.ai/threats/cve-2026-27971-qwik-remote-code-execution-via-server-deserialization  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-03-02. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-27971 · Severity: medium · CVSS 4 · Published 2026-03-02

Qwik is a JavaScript framework used for building web applications. An unsafe deserialization flaw in its server$ RPC (remote procedure call) mechanism allows attackers to execute arbitrary code on servers running Qwik without authentication. This enables full compromise of the affected server and any data it contains.

Technologies: [@builder.io/qwik (npm)](https://junglewise.ai/threats/technologies/builder-io-qwik). Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2026-27971 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-27971 being exploited in the wild.

**How severe is CVE-2026-27971?** Medium severity, with a CVSS score of 4, published 2 March 2026.

**Which products and versions are affected?** @builder.io/qwik (npm) SEMVER:introduced=0,fixed=1.19.1.

**Is there a fix for CVE-2026-27971?** Yes. @builder.io/qwik (npm): upgrade to 1.19.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-27971 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-27971?** Check whether you run @builder.io/qwik (npm) 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

- @builder.io/qwik (npm): upgrade to 1.19.1 or later

  ```sh
  npm install @builder.io/qwik@1.19.1
  ```


## Technical details

The vulnerability is a CWE-502 unsafe deserialization issue in the server$ RPC mechanism of Qwik versions ≤1.19.0. It allows unauthenticated attackers to execute arbitrary code on the server via a single HTTP request, provided that require() is available at runtime. The attack requires no privileges, no authentication, and minimal attack complexity. Successful exploitation grants remote code execution with full system access (confidentiality, integrity, and availability impact). The vulnerability was patched in version 1.19.1.

## Affected products

- Builder.io Qwik <=1.19.0

## Identifiers

- CVE-2026-27971
- GHSA-p9x5-jp3h-96mm

## Timeline

- 2026-03-02: disclosed
- 2026-03-02: patched: Version 1.19.1 released

## References

- [https://github.com/QwikDev/qwik/security/advisories/GHSA-p9x5-jp3h-96mm](https://github.com/QwikDev/qwik/security/advisories/GHSA-p9x5-jp3h-96mm)

## Related threats

- [Qwik server denial of service via malformed Resource thenable](https://junglewise.ai/threats/cve-2026-84994-qwik-crashing-any-qwik-server-via-resource-thenable)
- [Qwik mutation XSS due to improper HTML escaping in SSR](https://junglewise.ai/threats/cve-2024-41677-qwik-mutation-xss-due-to-improper-html-escaping-in-ssr)
- [BuilderIO Qwik code injection in PureFunctionSerializer](https://junglewise.ai/threats/cve-2023-1283-builderio-qwik-code-injection-in-purefunctionserializer)
- [Builder.io Qwik cross-site scripting in attribute handling](https://junglewise.ai/threats/cve-2023-0410-builder-io-qwik-cross-site-scripting-in-attribute-handling)