CVE-2019-14868: In ksh version 20120801, a flaw was found in the way it evaluates certain environment variables

Q: How do I fix CVE-2019-14868?

ksh: downgrade or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation; mac os x: upgrade to 10.15.5. Exact commands for each OS are on this page.

Q: Is CVE-2019-14868 being exploited?

CVE-2019-14868 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-2019-14868 affect?

CVE-2019-14868 affects ksh, debian linux, mac os x. Severity is high (CVSS 7.4). In ksh version 20120801, a flaw was found in the way it evaluates certain environment variables. An attacker could use this flaw to override or bypass environment restrictions to execute shell commands. Services and applications that allow

Q: How urgent is CVE-2019-14868?

Priority 49/100. High severity; On your watchlist

This month

HIGH 7.4WATCHLISTDOWNGRADEMITIGATEUPGRADE

CVE-2019-14868 is a high-severity flaw (CVSS 7.4) affecting ksh, debian linux, mac os x. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In ksh version 20120801, a flaw was found in the way it evaluates certain environment variables. An attacker could use this flaw to override or bypass environment restrictions to execute shell commands. Services and applications that allow remote unauthenticated attackers to provide one of those environment variables could allow them to exploit this issue remotely.

Why this priority

High severity
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	7.4 (High)
Attack vector	Local
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	1.4% (top 28%)
CISA exploited list	No
Weakness	CWE-77
Published	2020-04-02
Last modified	2026-06-17

Publisher (CNA): Red Hat, Inc. · Vendor: apple · debian · ksh project

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

Am I affected?

Timeline

2020-04-02 17:15 UTCPublished CVE record published
2026-06-17 02:19 UTCUpdated Record last modified

ksh project ksh DOWNGRADE

Affected: 20120801

Fixed in: no fixed release known

Safe to downgrade to: a release before 20120801

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 20120801 (Debian / Ubuntu)

apt-cache madison ksh sudo apt install ksh=<VERSION_BEFORE_20120801> sudo apt-mark hold ksh

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

dnf --showduplicates list ksh sudo dnf downgrade ksh-<VERSION_BEFORE_20120801> sudo dnf versionlock add ksh

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.

debian debian linux MITIGATE

Affected: 9.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

apple mac os x UPGRADE

Affected: < 10.15.5

Fixed in: 10.15.5

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

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-2019-14868?

ksh: downgrade or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation; mac os x: upgrade to 10.15.5. Exact commands for each OS are on this page.

Is CVE-2019-14868 being exploited?

CVE-2019-14868 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-2019-14868 affect?

CVE-2019-14868 affects ksh, debian linux, mac os x. Severity is high (CVSS 7.4). In ksh version 20120801, a flaw was found in the way it evaluates certain environment variables. An attacker could use this flaw to override or bypass environment restrictions to execute shell commands. Services and applications that allow

How urgent is CVE-2019-14868?

Priority 49/100. High severity; On your watchlist

Software pages

Debian vulnerabilities

References

← Back to latest CVEs