CVE-2019-20044

CVE-2019-20044 is a high-severity vulnerability in Zsh with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-273.

Key facts

• Severity: High (CVSS 3.x base score 7.8)
• CVSS v2: 7.2
• EPSS exploit prediction: 0% (39th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-273
• Affected product: Zsh
• Published: 2020-02-24
• Last modified: 2026-06-17

Description

In Zsh before 5.8, attackers able to execute commands can regain privileges dropped by the --no-PRIVILEGED option. Zsh fails to overwrite the saved uid, so the original privileges can be restored by executing MODULE_PATH=/dir/with/module zmodload with a module that calls setuid().

Frequently asked questions

What is CVE-2019-20044?

In Zsh before 5.8, attackers able to execute commands can regain privileges dropped by the --no-PRIVILEGED option. Zsh fails to overwrite the saved uid, so the original privileges can be restored by executing MODULE_PATH=/dir/with/module zmodload with a module that calls setuid().

How severe is CVE-2019-20044?

CVE-2019-20044 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2019-20044 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (39th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-20044?

CVE-2019-20044 primarily affects Zsh. In total, 31 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-20044?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2019-20044 published?

CVE-2019-20044 was published on 2020-02-24 and last updated on 2026-06-17.

References

• http://seclists.org/fulldisclosure/2020/May/49
• http://seclists.org/fulldisclosure/2020/May/53
• http://seclists.org/fulldisclosure/2020/May/55
• http://seclists.org/fulldisclosure/2020/May/59
• http://zsh.sourceforge.net/releases.html
• https://github.com/XMB5/zsh-privileged-upgrade
• https://lists.debian.org/debian-lts-announce/2020/03/msg00004.html
• https://lists.debian.org/debian-lts-announce/2020/12/msg00000.html
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FP64FFIZI2CKQOEAOI5A72PVQULE7ZZC/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PN5V7MPHRRP7QNHOEK56S7QGRU53WUN6/
• https://security.gentoo.org/glsa/202003-55
• https://support.apple.com/HT211168
• https://support.apple.com/HT211170
• https://support.apple.com/HT211171
• https://support.apple.com/HT211175
• https://support.apple.com/kb/HT211168
• https://support.apple.com/kb/HT211170
• https://support.apple.com/kb/HT211171
• https://support.apple.com/kb/HT211175
• https://www.zsh.org/mla/zsh-announce/141

Affected products (31)

• cpe:2.3:a:zsh:zsh:*:*:*:*:*:*:*:*
• cpe:2.3:o:fedoraproject:fedora:30:*:*:*:*:*:*:*
• cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*
• cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
• cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
• cpe:2.3:o:apple:ipados:*:*:*:*:*:*:*:*
• cpe:2.3:o:apple:iphone_os:*:*:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:*:*:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:10.13.6:-:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:10.13.6:security_update_2018-002:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:10.13.6:security_update_2018-003:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:10.13.6:security_update_2019-001:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:10.13.6:security_update_2019-002:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:10.13.6:security_update_2019-003:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:10.13.6:security_update_2019-004:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:10.13.6:security_update_2019-005:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:10.13.6:security_update_2019-006:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:10.13.6:security_update_2019-007:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:10.13.6:security_update_2020-001:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:10.13.6:security_update_2020-002:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:10.14.6:-:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:10.14.6:security_update_2019-001:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:10.14.6:security_update_2019-002:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:10.14.6:security_update_2019-004:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:10.14.6:security_update_2019-005:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:10.14.6:security_update_2019-006:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:10.14.6:security_update_2019-007:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:10.14.6:security_update_2020-001:*:*:*:*:*:*
• cpe:2.3:o:apple:mac_os_x:10.14.6:security_update_2020-002:*:*:*:*:*:*
• cpe:2.3:o:apple:tvos:*:*:*:*:*:*:*:*
• cpe:2.3:o:apple:watchos:*:*:*:*:*:*:*:*

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• CVE-2016-10714 — Critical (CVSS 9.8): In zsh before 5.3, an off-by-one error resulted in undersized buffers that were intended to support PATH_MAX characters.
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All CVEs affecting Zsh →

Other CWE-273 vulnerabilities

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• CVE-2021-36372 — Critical (CVSS 9.8): In Apache Ozone versions prior to 1.2.0, Initially generated block tokens are persisted to the metadata database and…
• CVE-2020-24361 — Critical (CVSS 9.8): SNMPTT before 1.4.2 allows attackers to execute shell code via EXEC, PREXEC, or unknown_trap_exec.
• CVE-2011-3350 — Critical (CVSS 9.8): masqmail 0.2.21 through 0.2.30 improperly calls seteuid() in src/log.c and src/masqmail.c that results in improper…
• CVE-2011-2921 — Critical (CVSS 9.8): ktsuss versions 1.4 and prior has the uid set to root and does not drop privileges prior to executing user specified…

Browse all CWE-273 vulnerabilities →