CVE-2021-30829
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA URI parsing issue was addressed with improved parsing. This issue is fixed in Security Update 2021-005 Catalina, macOS Big Sur 11.6. A local user may be able to execute arbitrary files.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceThis is a URI parsing vulnerability in macOS Catalina and Big Sur 11.6 that allows a local authenticated user to execute arbitrary files on the system. The vulnerability stems from improper handling of URI schemes during parsing, enabling path traversal or injection of malicious file paths.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data>= 10.15, <= 10.15.6= 10.15.7>= 11.0, < 11.6CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check installed macOS versionGo to Apple menu > About This Mac, or run 'sw_vers -productVersion' in TerminalAffected if Version is 10.15.7, or between 10.15.0 and 10.15.6, or between 11.0 and 11.5
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Confirm macOS nameRun 'sw_vers -productVersion' and note the major version number - 10.x is Catalina, 11.x is Big SurAffected if Running Catalina (10.15.x) or Big Sur (11.0-11.5)
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Verify patch status (optional)Check System Preferences > Software Update for available security updates, or inspect the installed security update history in TerminalAffected if Security Update 2021-005 for Catalina or the macOS Big Sur 11.6 security update has NOT been applied
You are affected if running macOS Catalina 10.15.x or macOS Big Sur 11.0-11.5 and the corresponding security updates have not been installed.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped11.6
Apply Apple Security Update 2021-005 for Catalina or the macOS Big Sur 11.6 security update to patch the URI parsing vulnerability. In enterprise environments, test for application compatibility before broad deployment.
Security Update 2021-005 for macOS Catalina (10.15.x) or macOS Big Sur 11.6
- Back up your Mac using Time Machine or another backup solution before applying any system updates
- Open System Preferences (on macOS 11) or System Preferences (on macOS 10.15)
- Click on 'Software Update' to check for available updates
- If Security Update 2021-005 Catalina appears (for macOS 10.15.x), click 'Install Now' or 'Update Now' to install the security update
- For macOS Big Sur 11.0-11.5.x, update to macOS Big Sur 11.6 by clicking 'Update Now' when it appears in Software Update
- Restart your Mac when prompted to complete the installation
- After restart, verify the update was applied by returning to Software Update and confirming no further security updates are available for this CVE
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation1.0 h
- Testing4.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,176.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-30829 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-30829 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data