CVE-2021-3391: MobileIron Mobile@Work through 2021-03-22 allows attackers to distinguish among valid, disabled, and nonexiste

Q: How do I fix CVE-2021-3391?

mobile\@work: upgrade to newer than 11.0.0.0.115r; mobile\@work: upgrade to newer than 12.11.1. Exact commands for each OS are on this page.

Q: Is CVE-2021-3391 being exploited?

CVE-2021-3391 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-3391 affect?

CVE-2021-3391 affects mobile\@work, mobile\@work. Severity is medium (CVSS 5.3). MobileIron Mobile@Work through 2021-03-22 allows attackers to distinguish among valid, disabled, and nonexistent user accounts by observing the number of failed login attempts needed to produce a Lockout error message

Q: How urgent is CVE-2021-3391?

Priority 41/100. Remotely exploitable, no login, no user action

This month

MEDIUM 5.3REMOTEUPGRADEUPGRADE

CVE-2021-3391 is a medium-severity flaw (CVSS 5.3) affecting mobile\@work, mobile\@work. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

MobileIron Mobile@Work through 2021-03-22 allows attackers to distinguish among valid, disabled, and nonexistent user accounts by observing the number of failed login attempts needed to produce a Lockout error message

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.2% (top 32%)
CISA exploited list	No
Published	2021-03-29
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: mobileiron

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

Am I affected?

Timeline

2021-03-29 20:15 UTCPublished CVE record published
2026-06-17 04:05 UTCUpdated Record last modified

mobileiron mobile\@work UPGRADE

Affected: <= 11.0.0.0.115r

Fixed in: newer than 11.0.0.0.115r

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 11.0.0.0.115r (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade mobilework

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade mobilework

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

mobileiron mobile\@work UPGRADE

Affected: <= 12.11.1

Fixed in: newer than 12.11.1

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 12.11.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade mobilework

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade mobilework

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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-2021-3391?

mobile\@work: upgrade to newer than 11.0.0.0.115r; mobile\@work: upgrade to newer than 12.11.1. Exact commands for each OS are on this page.

Is CVE-2021-3391 being exploited?

CVE-2021-3391 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-2021-3391 affect?

CVE-2021-3391 affects mobile\@work, mobile\@work. Severity is medium (CVSS 5.3). MobileIron Mobile@Work through 2021-03-22 allows attackers to distinguish among valid, disabled, and nonexistent user accounts by observing the number of failed login attempts needed to produce a Lockout error message

How urgent is CVE-2021-3391?

Priority 41/100. Remotely exploitable, no login, no user action

Related CVEs

CVE-2020-35138 CRITICAL 9.8 UPGRADE UPGRADE The MobileIron agents through 2021-03-22 for Android and iOS contain a hardcoded encryption key, used to encry
CVE-2020-35137 HIGH 7.5 UPGRADE UPGRADE The MobileIron agents through 2021-03-22 for Android and iOS contain a hardcoded API key, used to communicate
CVE-2014-5903 MEDIUM 5.4 DOWNGRADE The Mobile@Work (aka com.mobileiron) application 6.0.0.1.12R for Android does not verify X.509 certificates fr

References

← Back to latest CVEs