What is CVE-2018-20820?

CVE-2018-20820 is a medium-severity vulnerability in Dropbox Lepton, classified under Integer Overflow or Wraparound. CVSS score: 5.5/10. Published 2019-04-23.

How severe is CVE-2018-20820?

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

Integer overflow in Dropbox Lepton

CVE-2018-20820

read_ujpg in jpgcoder.cc in Dropbox Lepton 1.2.1 allows attackers to cause a denial-of-service (application runtime crash because of an integer overflow) via a crafted file.

Vulnerability class: Integer Overflow

Published 2019-04-23 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.010 (60.0th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 60th percentile — 60.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: 0.000

Affected products

Dropbox Lepton — versions 1.2.1

Weakness classification (CWE)

CWE-190 — Integer Overflow or Wraparound

References

github.com/dropbox/lepton/issues/111 (Exploit, Patch, Third Party Advisory)
github.com/dropbox/lepton/commit/6a5ceefac1162783fffd9506a3de39c85c725761 (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2018-20820?: CVE-2018-20820 is a medium-severity vulnerability in Dropbox Lepton, classified under Integer Overflow or Wraparound. CVSS score: 5.5/10. Published 2019-04-23.
How severe is CVE-2018-20820?: Medium severity. CVSS v3 base score is 5.5 out of 10.