What is CVE-2020-23556?

CVE-2020-23556 is a high-severity vulnerability in Irfanview, classified under Out-of-bounds Write. CVSS score: 7.8/10. Published 2022-09-16.

How severe is CVE-2020-23556?

High severity. CVSS v3 base score is 7.8 out of 10.

Is CVE-2020-23556 known to be exploited?

3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Buffer overflow in Irfanview

CVE-2020-23556

IrfanView 4.54 allows a user-mode write access violation starting at FORMATS!GetPlugInInfo+0x0000000000007e28.

Vulnerability class: Buffer Overflow

Published 2022-09-16 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.003 (23.7th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 24th percentile — 23.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.000

Affected products

Irfanview — versions 4.54

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

Public proof-of-concept exploits

References

www.irfanview.com/plugins.htm (Product)
github.com/nhiephon/Research (Third Party Advisory)

Frequently asked questions

What is CVE-2020-23556?: CVE-2020-23556 is a high-severity vulnerability in Irfanview, classified under Out-of-bounds Write. CVSS score: 7.8/10. Published 2022-09-16.
How severe is CVE-2020-23556?: High severity. CVSS v3 base score is 7.8 out of 10.
Is CVE-2020-23556 known to be exploited?: 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.