CVE-2020-11799: Z-Cron 5.6 Build 04 allows an unprivileged attacker to elevate privileges by modifying a privileged user's tas

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CRITICAL 9.8REMOTEDOWNGRADE

CVE-2020-11799 is a critical-severity flaw (CVSS 9.8) affecting z-cron. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Z-Cron 5.6 Build 04 allows an unprivileged attacker to elevate privileges by modifying a privileged user's task. This can also affect all users who are signed in on the system if a shell is placed in a location that other unprivileged users have access to.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

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

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.2% (top 32%)
CISA exploited list	No
Weakness	CWE-269
Published	2020-04-15
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: z-cron

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

Am I affected?

Timeline

2020-04-15 19:15 UTCPublished CVE record published
2026-06-17 02:50 UTCUpdated Record last modified

z-cron z-cron DOWNGRADE

Affected: 5.6 build_04

Fixed in: no fixed release known

Safe to downgrade to: a release before 5.6

1. Check installed version

apt-cache policy z-cron || rpm -q z-cron || z-cron --version

2. No fixed release: DOWNGRADE to a release before 5.6 (Debian / Ubuntu)

apt-cache madison z-cron sudo apt install z-cron=<VERSION_BEFORE_5.6> sudo apt-mark hold z-cron

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

dnf --showduplicates list z-cron sudo dnf downgrade z-cron-<VERSION_BEFORE_5.6> sudo dnf versionlock add z-cron

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-2020-11799?

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

Is CVE-2020-11799 being exploited?

CVE-2020-11799 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-2020-11799 affect?

CVE-2020-11799 affects z-cron. Severity is critical (CVSS 9.8). Z-Cron 5.6 Build 04 allows an unprivileged attacker to elevate privileges by modifying a privileged user's task. This can also affect all users who are signed in on the system if a shell is placed in a location that other unprivileged users

How urgent is CVE-2020-11799?

Priority 61/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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