How severe is CVE-2025-64721?

CVE-2025-64721 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2025-64721 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-64721?

CVE-2025-64721 affects Sandboxie-plus Sandboxie. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-64721?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2025-64721 have an EU (EUVD) identifier?

Yes. CVE-2025-64721 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-202846.

When was CVE-2025-64721 published?

CVE-2025-64721 was published on 2025-12-11 and last updated on 2026-06-17.

CVE-2025-64721

CVE-2025-64721 is a critical-severity vulnerability in Sandboxie-plus Sandboxie with a CVSS 3.x base score of 10.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-190.

Key facts

Severity: Critical (CVSS 3.x base score 10.0)
CVSS v4: 9.9
EPSS exploit prediction: 1% (45th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-202846
Weakness: CWE-190
Affected product: Sandboxie-plus Sandboxie
Published: 2025-12-11
Last modified: 2026-06-17

Description

Sandboxie is a sandbox-based isolation software for 32-bit and 64-bit Windows NT-based operating systems. In versions 1.16.6 and below, the SYSTEM-level service SbieSvc.exe exposes SbieIniServer::RC4Crypt to sandboxed processes. The handler adds a fixed header size to a caller-controlled value_len without overflow checking. A large value_len (e.g., 0xFFFFFFF0) wraps the allocation size, causing a heap overflow when attacker data is copied into the undersized buffer. This allows sandboxed processes to execute arbitrary code as SYSTEM, fully compromising the host. This issue is fixed in version 1.16.7.

Frequently asked questions

What is CVE-2025-64721?: Sandboxie is a sandbox-based isolation software for 32-bit and 64-bit Windows NT-based operating systems. In versions 1.16.6 and below, the SYSTEM-level service SbieSvc.exe exposes SbieIniServer::RC4Crypt to sandboxed processes. The handler adds a fixed header size to a caller-controlled value_len without overflow checking. A large value_len (e.g., 0xFFFFFFF0) wraps the allocation size, causing a heap overflow when attacker data is copied into the undersized buffer. This allows sandboxed processes to execute arbitrary code as SYSTEM, fully compromising the host. This issue is fixed in version 1.16.7.
How severe is CVE-2025-64721?: CVE-2025-64721 has a CVSS 3.x base score of 10.0, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2025-64721 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-64721?: CVE-2025-64721 affects Sandboxie-plus Sandboxie. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-64721?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2025-64721 have an EU (EUVD) identifier?: Yes. CVE-2025-64721 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-202846.
When was CVE-2025-64721 published?: CVE-2025-64721 was published on 2025-12-11 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:sandboxie-plus:sandboxie:*:*:*:*:plus:*:*:*

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