CVE-2018-20820: read_ujpg in jpgcoder.cc in Dropbox Lepton 1.2.1 allows attackers to cause a denial-of-service (application ru

This month

MEDIUM 5.5DOWNGRADE

CVE-2018-20820 is a medium-severity flaw (CVSS 5.5) affecting lepton. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	1.0% (top 38%)
CISA exploited list	No
Weakness	CWE-190
Published	2019-04-23
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: dropbox

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2019-04-23 14:29 UTCPublished CVE record published
2026-06-17 01:53 UTCUpdated Record last modified

dropbox lepton DOWNGRADE

Affected: 1.2.1

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.2.1

1. Check installed version

apt-cache policy lepton || rpm -q lepton || lepton --version

2. No fixed release: DOWNGRADE to a release before 1.2.1 (Debian / Ubuntu)

apt-cache madison lepton sudo apt install lepton=<VERSION_BEFORE_1.2.1> sudo apt-mark hold lepton

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list lepton sudo dnf downgrade lepton-<VERSION_BEFORE_1.2.1> sudo dnf versionlock add lepton

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2018-20820?

lepton: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2018-20820 being exploited?

CVE-2018-20820 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2018-20820 affect?

CVE-2018-20820 affects lepton. Severity is medium (CVSS 5.5). 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.

How urgent is CVE-2018-20820?

Priority 40/100. Public exploit reference

Software pages

Dropbox vulnerabilities

Related CVEs

CVE-2022-4104 MEDIUM 5.5 DOWNGRADE A loop with an unreachable exit condition can be triggered by passing a crafted JPEG file to the Lepton image
CVE-2022-26181 HIGH 7.8 DOWNGRADE Dropbox Lepton v1.2.1-185-g2a08b77 was discovered to contain a heap-buffer-overflow in the function aligned_de
CVE-2018-20819 HIGH 7.8 DOWNGRADE io/ZlibCompression.cc in the decompression component in Dropbox Lepton 1.2.1 allows attackers to cause a denia
CVE-2018-12108 MEDIUM 5.5 DOWNGRADE An issue was discovered in Dropbox Lepton 1.2.1
CVE-2017-8891 MEDIUM 5.5 DOWNGRADE Dropbox Lepton 1.2.1 allows DoS (SEGV and application crash) via a malformed lepton file because the code does

References

← Back to latest CVEs