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CVE-2021-40531

Status: ModifiedCritical (9.8)—PoC
Severity9.8Critical · CVSS 3.1
Exploitation probability33 %higher than 98% of CVEs
Active exploitationNonot in the CISA catalog
Public exploitAvailableProof of concept on GitHub (unverified)

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

Base score
9.8
Version
3.1
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days
33 %
Percentile among all scored CVEs
98
Score date
10/21/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Public exploits

Exploit code or detection templates are publicly available. This is not the same as confirmed active exploitation (KEV), but it raises the risk: patch with priority.

⚠️ GitHub proofs of concept are not verified: some are fake or contain malware. Never run them outside an isolated lab.

Affected technologies (1)

Sketch — Sketch

CWEs

References

Show 4 references

Raw JSON (NVD)

Show
{
  "id": "CVE-2021-40531",
  "cveTags": [],
  "metrics": {
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        "type": "Primary",
        "source": "nvd@nist.gov",
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          "vectorString": "AV:N/AC:L/Au:N/C:P/I:P/A:P",
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  "affected": [
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      "source": "af854a3a-2127-422b-91ae-364da2661108"
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    {
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      "tags": [
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        "Release Notes",
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      "source": "af854a3a-2127-422b-91ae-364da2661108"
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  "vulnStatus": "Modified",
  "weaknesses": [
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      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-434"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    },
    {
      "lang": "es",
      "value": "Sketch antes de 75 permite utilizar las fuentes de la biblioteca para eludir la cuarentena de archivos. Los archivos se descargan y abren automáticamente, sin el atributo extendido com.apple.quarantine. Esto da lugar a la ejecución remota de código, como lo demuestra CommandString en un perfil de terminal a Terminal.app"
    }
  ],
  "lastModified": "2026-06-17T04:07:06.107",
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    {
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        {
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          "cpeMatch": [
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              "versionEndExcluding": "75"
            }
          ],
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  "sourceIdentifier": "cve@mitre.org"
}