CVE-2021-30657
A logic issue was addressed with improved state management. This issue is fixed in macOS Big Sur 11.3, Security Update 2021-002 Catalina. A malicious application may bypass Gatekeeper checks. Apple is aware of a report that this issue may have been actively exploited..
- CVSS
- 5.5Mediumscored by CISA
- Exploited in the wild
- Yes, in CISA KEV since 3 Nov 2021CISA deadline for US federal agencies: 17 Nov 2021public exploit code
- EPSS
- 68.5%chance of exploitation in the next 30 daystop 0.7% of scored CVEsFIRST score of 11 Nov 2026
- Fix
- Patch availablesee the advisories in the references
- Published
- 8 Sept 2021analysed here 12 Nov 2026
Do first. Apply updates per vendor instructions. (CISA's required action for this KEV entry)
Summary
Triage
The summary, impact and action text on this page are written by our AI analysis pipeline, or taken from the NVD description when a CVE was imported from NVD. They are not the vendor's wording: check them against the sources. A longer AI executive summary and technical analysis are generated for signed-in accounts on the Max plan.
Affected products
| Product | Affected versions | Vendor says fixed in |
|---|---|---|
| Apple macOS | < 11.3< 2021Vendor says fixed in: not stated |
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.
Products named in our analysis
- apple:mac_os_x
- apple:macos
Fix and mitigation
WAF and other mitigations
Can a WAF block it? No. The attack needs local access to the machine, so a WAF is not on its path.
Also consider: patch
Based on the attack vector (local or physical access). We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Remediation steps (AI-written)
Step-by-step remediation is generated for accounts on the Max plan, for CVEs that match a technology in their stack. Add this technology to your stack to see the fix checklist.
Exploitation evidence
- CISA KEV catalog
- Listed since 3 Nov 2021.
- CISA due date
- 17 Nov 2021, the remediation deadline for US federal agencies
- CISA required action
- Apply updates per vendor instructions.
- Public exploit code
- Yes: 1 Metasploit module · 1 GitHub proof of concept
- CISA SSVC
- exploitation active, automatable no, technical impact partialAssessed by CISA 29 Jan 2025 (SSVC 2.0.3). Exploitation is none, poc (public proof of concept) or active.
Metasploit
- exploit/osx/browser/osx_gatekeeper_bypassexploit, rank manual
GitHub proofs of concept
- shubham0d/CVE-2021-3065729 stars
Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.
Timeline
- 8 Sept 2021Published
- 3 Nov 2021Added to CISA KEV (exploited in the wild)55 days later
- 7 Nov 2021First public exploit or proof of concept4 days later
- 17 Nov 2021CISA remediation due date (US federal agencies)10 days later
- 29 Jan 2025CISA SSVC assessment: exploitation active1,170 days (about 3 years) later
- 21 Oct 2025CVE record last updated265 days (about 9 months) later
- 12 Nov 2026Analysed by vulneraibility.com387 days (about 1 year) later
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
| Metric | Value | What it means |
|---|---|---|
| Attack vector | LocalLocal access required (shell, logged-in user). | Local access required (shell, logged-in user). |
| Attack complexity | LowRepeatable attack, no special conditions. | Repeatable attack, no special conditions. |
| Privileges required | NoneThe attacker needs no prior access. | The attacker needs no prior access. |
| User interaction | RequiredA victim must click, open or otherwise cooperate. | A victim must click, open or otherwise cooperate. |
| Scope | UnchangedImpact stays within the vulnerable component. | Impact stays within the vulnerable component. |
| Confidentiality | NoneNo data disclosure. | No data disclosure. |
| Integrity | HighComplete modification possible. | Complete modification possible. |
| Availability | NoneThe service stays up. | The service stays up. |
Common questions
Is CVE-2021-30657 being exploited?
Yes. CVE-2021-30657 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.
How severe is CVE-2021-30657?
CVE-2021-30657 is rated Medium with a CVSS score of 5.5. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2021-30657?
Yes. A fix has been recorded for CVE-2021-30657. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2021-30657 affect?
CVE-2021-30657 affects apple:mac_os_x, apple:macos. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
References
3 references in the CVE record, grouped by the tags the record gives them.
Other links (3)
- support.apple.com /en-us/HT212325
- support.apple.com /en-us/HT212326
- cisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30657
Where the data on this page comes from
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA KEV catalog: exploitation, date added, due date
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
- Metasploit Framework: exploit and scanner modules
- PoC-in-GitHub: GitHub repositories that claim a proof of concept
Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.
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