What is CVE-2019-19703?

CVE-2019-19703 is a medium-severity vulnerability in Jetbrains Ktor, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 6.1/10. Published 2019-12-10.

How severe is CVE-2019-19703?

Medium severity. CVSS v3 base score is 6.1 out of 10.

Open Redirect in Jetbrains Ktor

CVE-2019-19703

In Ktor through 1.2.6, the client resends data from the HTTP Authorization header to a redirect location.

Vulnerability class: Open Redirect

Published 2019-12-10 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.006 (49.8th percentile), scored 2026-10-20.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 50th percentile — 49.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

Jetbrains Ktor

Weakness classification (CWE)

CWE-601 — URL Redirection to Untrusted Site (Open Redirect)

References

github.com/ktorio/ktor/issues/1467 (Exploit, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2019-19703?: CVE-2019-19703 is a medium-severity vulnerability in Jetbrains Ktor, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 6.1/10. Published 2019-12-10.
How severe is CVE-2019-19703?: Medium severity. CVSS v3 base score is 6.1 out of 10.