What is CVE-2020-23566?

CVE-2020-23566 is a medium-severity vulnerability in Irfanview, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 5.5/10. Published 2021-11-05.

How severe is CVE-2020-23566?

Medium severity. CVSS v3 base score is 5.5 out of 10.

Vulnerability in Irfanview

CVE-2020-23566

Irfanview v4.53 was discovered to contain an infinity loop via JPEG2000!ShowPlugInSaveOptions_W+0x1ecd8.

Published 2021-11-05 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.008 (55.4th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 55th percentile — 55.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000

Affected products

Irfanview — versions 4.53

Weakness classification (CWE)

CWE-835 — Loop with Unreachable Exit Condition (Infinite Loop)

References

github.com/KamasuOri/publicResearch/tree/master/poc/irfanview/1 (Third Party Advisory)

Frequently asked questions

What is CVE-2020-23566?: CVE-2020-23566 is a medium-severity vulnerability in Irfanview, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 5.5/10. Published 2021-11-05.
How severe is CVE-2020-23566?: Medium severity. CVSS v3 base score is 5.5 out of 10.