In Zsh before 5.8, attackers able to execute commands can regain privileges dropped by the --no-PRIVILEGED option.
Noroxi assessment
Priority: Monitor (action score 31/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.49% (FIRST EPSS).
- Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
- Fixed version: zsh-html (AlmaLinux:8) 5.5.1-6.el8_1.2; zsh (Alpine:v3.12) 5.8-r0; zsh (Debian:12) 5.8-1.
Low priority for now. Upgrade to zsh-html (AlmaLinux:8) 5.5.1-6.el8_1.2; zsh (Alpine:v3.12) 5.8-r0; zsh (Debian:12) 5.8-1 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
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().
- Published
- Feb 24, 2020
- Updated
- Jun 16, 2026
- EPSS
- 0.5% · 41th percentile
- CWE
- CWE-273
Report tools
Action score
31
Monitor
Low priority for now.
- CVSS
- 31 / 40 · 7.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.5%
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| zsh | zsh | cpe:2.3:a:zsh:zsh |
| apple | macos | cpe:2.3:o:apple:macos |
| linux | linux kernel | cpe:2.3:o:linux:linux_kernel |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| apple | ipados | cpe:2.3:o:apple:ipados |
| apple | iphone os | cpe:2.3:o:apple:iphone_os |
| apple | mac os x | cpe:2.3:o:apple:mac_os_x |
| apple | tvos | cpe:2.3:o:apple:tvos |
| apple | watchos | cpe:2.3:o:apple:watchos |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- apple ipadosbefore 13.5
- apple iphone osbefore 13.5
- apple mac os x10.13.0 and later · before 10.13.6
- apple mac os x10.15 and later · before 10.15.5
- apple mac os xbefore 10.15.5
- apple mac os x10.14.0 and later · before 10.14.6
- apple mac os x10.13.6
- apple mac os x10.14.6
- apple tvosbefore 13.4.5
- apple watchosbefore 6.2.5
- debian debian linux8.0
- debian debian linux9.0
- fedoraproject fedora30
- fedoraproject fedora31
- zsh zshbefore 5.8
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:8 | zsh-html | before 5.5.1-6.el8_1.2 | 5.5.1-6.el8_1.2 |
| Alpine:v3.12 | zsh | before 5.8-r0 | 5.8-r0 |
| Debian:12 | zsh | before 5.8-1 | 5.8-1 |
| Debian:8 | zsh | before 5.0.7-5+deb8u1 | 5.0.7-5+deb8u1 |
| Debian:9 | zsh | before 5.3.1-4+deb9u1 | 5.3.1-4+deb9u1 |
| openSUSE:Leap 15.3 | zsh | before 5.6-7.5.1 | 5.6-7.5.1 |
| openSUSE:Tumbleweed | zsh | before 5.8-7.7 | 5.8-7.7 |
| Red Hat:enterprise_linux:6::client | zsh | before 0:4.3.11-11.el6_10 | 0:4.3.11-11.el6_10 |
| Red Hat:enterprise_linux:6::client | zsh-debuginfo | before 0:4.3.11-11.el6_10 | 0:4.3.11-11.el6_10 |
| Red Hat:enterprise_linux:6::client | zsh-html | before 0:4.3.11-11.el6_10 | 0:4.3.11-11.el6_10 |
| Red Hat:enterprise_linux:7::client | zsh | before 0:5.0.2-34.el7_7.2 | 0:5.0.2-34.el7_7.2 |
| Red Hat:enterprise_linux:7::client | zsh-debuginfo | before 0:5.0.2-34.el7_7.2 | 0:5.0.2-34.el7_7.2 |
| Red Hat:enterprise_linux:7::client | zsh-html | before 0:5.0.2-34.el7_7.2 | 0:5.0.2-34.el7_7.2 |
| Red Hat:enterprise_linux:8::appstream | zsh-html | before 0:5.5.1-6.el8_1.2 | 0:5.5.1-6.el8_1.2 |
| Red Hat:enterprise_linux:8::baseos | zsh | before 0:5.5.1-6.el8_1.2 | 0:5.5.1-6.el8_1.2 |
| Red Hat:enterprise_linux:8::baseos | zsh-debuginfo | before 0:5.5.1-6.el8_1.2 | 0:5.5.1-6.el8_1.2 |
| Red Hat:enterprise_linux:8::baseos | zsh-debugsource | before 0:5.5.1-6.el8_1.2 | 0:5.5.1-6.el8_1.2 |
| Red Hat:rhel_e4s:8.0::appstream | zsh-html | before 0:5.5.1-6.el8_0.2 | 0:5.5.1-6.el8_0.2 |
| Red Hat:rhel_e4s:8.0::baseos | zsh | before 0:5.5.1-6.el8_0.2 | 0:5.5.1-6.el8_0.2 |
| Red Hat:rhel_e4s:8.0::baseos | zsh-debuginfo | before 0:5.5.1-6.el8_0.2 | 0:5.5.1-6.el8_0.2 |
| Red Hat:rhel_e4s:8.0::baseos | zsh-debugsource | before 0:5.5.1-6.el8_0.2 | 0:5.5.1-6.el8_0.2 |
| Rocky Linux:8 | zsh | before 0:5.5.1-6.el8_1.2 | 0:5.5.1-6.el8_1.2 |
| SUSE:HPE Helion OpenStack 8 | zsh | before 5.0.5-6.19.1 | 5.0.5-6.19.1 |
| SUSE:Linux Enterprise High Performance Computing 15-ESPOS | zsh | before 5.6-3.11.1 | 5.6-3.11.1 |
+2
Same product
zsh: all recordsOther highest-scoring records for the same primary product.
- CVE-2018-13259An issue was discovered in zsh before 5.6.40Plan
- CVE-2018-0502An issue was discovered in zsh before 5.6.40Plan
- CVE-2018-7548In subst.c in zsh through 5.4.2, there is a NULL pointer dereference when using ${(PA)...} on an empty array result.40Plan
- CVE-2017-18206In utils.c in zsh before 5.4, symlink expansion had a buffer overflow.40Plan
- CVE-2016-10714In zsh before 5.3, an off-by-one error resulted in undersized buffers that were intended to support PATH_MAX characters.40Plan
- CVE-2014-10071In exec.c in zsh before 5.0.7, there is a buffer overflow for very long fds in the ">& fd" syntax.40Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| almalinux:zsh-html | 5.5.1-6.el8_1.2 · AlmaLinux:8 | Package registry (OSV) |
| alpine:zsh | 5.8-r0 · Alpine:v3.12 | Package registry (OSV) |
| debian:zsh | 5.8-1 · Debian:12 | Package registry (OSV) |
| opensuse:zsh | 5.6-7.5.1 · openSUSE:Leap 15.3 | Package registry (OSV) |
| red hat:zsh | 0:5.0.2-34.el7_7.2 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:zsh-debuginfo | 0:5.0.2-34.el7_7.2 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:zsh-debugsource | 0:5.5.1-6.el8_1.2 · Red Hat:enterprise_linux:8::baseos | Package registry (OSV) |
| red hat:zsh-html | 0:5.0.2-34.el7_7.2 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| rocky linux:zsh | 0:5.5.1-6.el8_1.2 · Rocky Linux:8 | Package registry (OSV) |
| suse:zsh | 5.6-3.11.1 · SUSE:Linux Enterprise High Performance Computing 15-ESPOS | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-273 · Improper Check for Dropped PrivilegesCVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (19 more)Show less
- seclists.org/fulldisclosure/2020/May/53
- seclists.org/fulldisclosure/2020/May/55
- seclists.org/fulldisclosure/2020/May/59
- zsh.sourceforge.net/releases.html
- github.com/XMB5/zsh-privileged-upgrade
- lists.debian.org/debian-lts-announce/2020/03/msg00004.html
- lists.debian.org/debian-lts-announce/2020/12/msg00000.html
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FP64FFIZI2CKQOEAOI5A72PVQULE7ZZC/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PN5V7MPHRRP7QNHOEK56S7QGRU53WUN6/
- security.gentoo.org/glsa/202003-55
- support.apple.com/HT211168
- support.apple.com/HT211170
- support.apple.com/HT211171
- support.apple.com/HT211175
- support.apple.com/kb/HT211168
- support.apple.com/kb/HT211170
- support.apple.com/kb/HT211171
- support.apple.com/kb/HT211175
- www.zsh.org/mla/zsh-announce/141
Vendor advisories and official records. Exploit/PoC links are deliberately left out.