CVE-2021-45444
HIGHCVSS 7.8/10EPSS 1.98%
Last modified
CVE-2021-45444 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. In zsh before 5.8.1, an attacker can achieve code execution if they control a command output inside the prompt, as demonstrated by a %F argument. This occurs because of recursive PROMPT_SUBST expansion.. EPSS estimates a 1.98% chance of exploitation in the next 30 days.
Description
In zsh before 5.8.1, an attacker can achieve code execution if they control a command output inside the prompt, as demonstrated by a %F argument. This occurs because of recursive PROMPT_SUBST expansion.
Metrics
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Affected Software
| Vendor | Product | Versions | Update |
|---|---|---|---|
| Zsh | Zsh | < 5.8.1 | — |
| Fedoraproject | Fedora | 34 | — |
| Fedoraproject | Fedora | 35 | — |
| Debian | Debian Linux | 9.0 | — |
| Debian | Debian Linux | 10.0 | — |
| Debian | Debian Linux | 11.0 | — |
| Apple | Mac Os X | >= 10.15, < 10.15.7 | — |
| Apple | Mac Os X | 10.15.7 | Security Update 2020 |
| Apple | Macos | >= 11.0, < 11.6.6 | — |
| Apple | Macos | >= 12.0.0, < 12.4 | — |
References
- http://seclists.org/fulldisclosure/2022/May/33Mailing List, Third Party Advisory
- http://seclists.org/fulldisclosure/2022/May/35Mailing List, Third Party Advisory
- http://seclists.org/fulldisclosure/2022/May/38Mailing List, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2022/02/msg00020.htmlMailing List, Third Party Advisory
- https://support.apple.com/kb/HT213255Third Party Advisory
- https://support.apple.com/kb/HT213256Third Party Advisory
- https://support.apple.com/kb/HT213257Third Party Advisory
- https://vuln.ryotak.me/advisories/63Third Party Advisory
- https://www.debian.org/security/2022/dsa-5078Third Party Advisory
- https://zsh.sourceforge.io/releases.htmlRelease Notes, Third Party Advisory
- http://seclists.org/fulldisclosure/2022/May/33Mailing List, Third Party Advisory
- http://seclists.org/fulldisclosure/2022/May/35Mailing List, Third Party Advisory
- http://seclists.org/fulldisclosure/2022/May/38Mailing List, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2022/02/msg00020.htmlMailing List, Third Party Advisory
- https://support.apple.com/kb/HT213255Third Party Advisory
- https://support.apple.com/kb/HT213256Third Party Advisory
- https://support.apple.com/kb/HT213257Third Party Advisory
- https://vuln.ryotak.me/advisories/63Third Party Advisory
- https://www.debian.org/security/2022/dsa-5078Third Party Advisory
- https://zsh.sourceforge.io/releases.htmlRelease Notes, Third Party Advisory
Timeline
- Published
- Last Modified
- Status
- Modified
Frequently Asked Questions
What is CVE-2021-45444?
In zsh before 5.8.1, an attacker can achieve code execution if they control a command output inside the prompt, as demonstrated by a %F argument. This occurs because of recursive PROMPT_SUBST expansion.
How severe is CVE-2021-45444?
CVE-2021-45444 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 1.98% probability of exploitation in the next 30 days.
How do I fix CVE-2021-45444?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
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