How severe is CVE-2026-34464?

CVE-2026-34464 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-34464 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-34464?

CVE-2026-34464 affects Sandboxie-plus Sandboxie. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-34464?

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

Does CVE-2026-34464 have an EU (EUVD) identifier?

Yes. CVE-2026-34464 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-27464.

When was CVE-2026-34464 published?

CVE-2026-34464 was published on 2026-05-05 and last updated on 2026-06-17.

CVE-2026-34464

CVE-2026-34464 is a high-severity vulnerability in Sandboxie-plus Sandboxie with a CVSS 3.x base score of 8.8. 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-121.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v4: 8.8
EPSS exploit prediction: 0% (7th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-27464
Weakness: CWE-121
Affected product: Sandboxie-plus Sandboxie
Published: 2026-05-05
Last modified: 2026-06-17

Description

Sandboxie-Plus is an open source sandbox-based isolation software for Windows. In versions 1.17.2 and earlier, NamedPipeServer::OpenHandler copies the server field from NAMED_PIPE_OPEN_REQ into a fixed WCHAR pipename[160] stack buffer using wcscat without verifying null termination. The handler only enforces a minimum packet size, and since the service pipe accepts variable-length messages, a sandboxed caller can fill the server[48] field with non-zero data and append additional controlled wide characters after the structure. wcscat then reads past the fixed field and overflows the stack buffer in the SYSTEM service. This message is restricted to sandboxed callers, making it a sandbox escape vector. This can lead to a crash of the SbieSvc service or potential code execution as SYSTEM. This issue has been fixed in version 1.17.3.

Frequently asked questions

What is CVE-2026-34464?: Sandboxie-Plus is an open source sandbox-based isolation software for Windows. In versions 1.17.2 and earlier, NamedPipeServer::OpenHandler copies the server field from NAMED_PIPE_OPEN_REQ into a fixed WCHAR pipename[160] stack buffer using wcscat without verifying null termination. The handler only enforces a minimum packet size, and since the service pipe accepts variable-length messages, a sandboxed caller can fill the server[48] field with non-zero data and append additional controlled wide characters after the structure. wcscat then reads past the fixed field and overflows the stack buffer in the SYSTEM service. This message is restricted to sandboxed callers, making it a sandbox escape vector. This can lead to a crash of the SbieSvc service or potential code execution as SYSTEM. This issue has been fixed in version 1.17.3.
How severe is CVE-2026-34464?: CVE-2026-34464 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-34464 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-34464?: CVE-2026-34464 affects Sandboxie-plus Sandboxie. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-34464?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-34464 have an EU (EUVD) identifier?: Yes. CVE-2026-34464 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-27464.
When was CVE-2026-34464 published?: CVE-2026-34464 was published on 2026-05-05 and last updated on 2026-06-17.

References

https://github.com/sandboxie-plus/Sandboxie/security/advisories/GHSA-cf8x-f33g-vwfg

Affected products (1)

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

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