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CVE-2025-66034

Status: AnalyzedCritical (9.8)—

fontTools is a library for manipulating fonts, written in Python. In versions from 4.33.0 to before 4.60.2, the fonttools varLib (or python3 -m fontTools.varLib) script has an arbitrary file write vulnerability that leads to remote code execution when a malicious .designspace file is processed. The vulnerability affects the main() code path of fontTools.varLib, used by the fonttools varLib CLI and any code that invokes fontTools.varLib.main(). This issue has been patched in version 4.60.2.

CVSS

Exploitation probability (EPSS)

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).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

CVE en biblioteca Python (fonttools) con vector CVSS AV:N/AC:L/PR:N: acceso remoto sin privilegios ni interacción. Archivo .designspace malicioso provoca ejecución de código remoto (T1059) y corrupción de fuentes (T1565.002).

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Privileged Account ManagementVulnerability ScanningRestrict Web-Based ContentNetwork SegmentationLimit Software InstallationLimit Access to Resource Over Network

Affected technologies (1)

Fonttools — Fonttools

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2025-66034",
  "cveTags": [],
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