CVE-2021-40531

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-05-24. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Elevated
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 33%CVSS: 9.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Sketch before 75 allows library feeds to be used to bypass file quarantine. Files are automatically downloaded and opened, without the com.apple.quarantine extended attribute. This results in remote code execution, as demonstrated by CommandString in a terminal profile to Terminal.app.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
65(Track*)
EG Risk 65/100SSVC: Track*

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation40% × 40%
Automatability30% × 15%
Action: Watch closely — could escalate to Attend.
EPSS
98.2%
KEV
Not listed

Published

September 6, 2021

Last Modified

November 21, 2024

Advisory Details (2)

Auto-updated Jun 20, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic

What’s New with Sketch — Latest Updates and Features · Sketch

https://www.sketch.com/updates/#version-75
generic🟡 PoC Available

Using CVE-2021-40531 for RCE with Sketch | Jon Palmisciano

https://jonpalmisc.com/2021/11/22/cve-2021-40531

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 8× in last 7d / 36× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-23 14:16 UTCEPSS rescore
  2. 2026-07-23 02:04 UTCEG score recompute
  3. 2026-07-22 22:50 UTCEG score recompute
  4. 2026-07-22 14:06 UTCEPSS rescore
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  1. 2026-07-01 15:04 UTCEPSS rescore
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  42. 2026-06-04 13:10 UTCEPSS rescore
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  44. 2026-06-02 20:11 UTCEPSS rescore
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  46. 2026-06-01 13:50 UTCEPSS rescore
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  48. 2026-05-31 22:29 UTCEPSS rescore
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  50. 2026-05-31 00:15 UTCEPSS rescore
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  57. 2026-05-26 13:42 UTCEPSS rescore
  58. 2026-05-26 13:42 UTCEPSS rescore
  59. 2026-05-26 11:01 UTCEG score recompute
  60. 2026-05-26 11:01 UTCGHSA enrichment
  61. 2026-05-26 07:17 UTCEPSS rescore
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  63. 2026-05-26 07:17 UTCEPSS rescore
  64. 2026-05-24 18:42 UTCOSV refresh

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCjonpalmisc/CVE-2021-40531
    First seen Nov 19, 2021

    Quarantine bypass and RCE vulnerability in Sketch (proof-of-concept)

    Open source ↗

Frequently asked(5)

What is CVE-2021-40531?
CVE-2021-40531 is a critical vulnerability published on September 6, 2021. Sketch before 75 allows library feeds to be used to bypass file quarantine. Files are automatically downloaded and opened, without the com.apple.quarantine extended attribute. This results in remote code execution, as demonstrated by CommandString in a terminal profile to Terminal.app.
When was CVE-2021-40531 disclosed?
CVE-2021-40531 was first published in the National Vulnerability Database on September 6, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-40531 actively exploited?
CVE-2021-40531 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 98.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-40531?
CVE-2021-40531 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2021-40531?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-40531, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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