Deserialization in Qwik

CVE-2026-27971

Qwik is a performance focused javascript framework. qwik <=1.19.0 is vulnerable to RCE due to an unsafe deserialization vulnerability in the server$ RPC mechanism that allows any unauthenticated user to execute arbitrary code on the server with a single HTTP request. Affects any deployment where require() is available at runtime. This vulnerability is fixed in 1.19.1.

Vulnerability class: Insecure Deserialization

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.029 (86.3th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 86th percentile — 86.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-27971: fell from 0.054 to 0.029.

EPSS over last 30 days · oldest: 0.054 · newest: 0.029 · change: -0.025

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2026-27971?
CVE-2026-27971 is a critical-severity vulnerability in Qwik, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2026-03-03.
How severe is CVE-2026-27971?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2026-27971 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.