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CVE-2026-34464: Sandboxie-Plus Sandboxie Stack Buffer Overflow (CVSS 8.8)

CVE-2026-34464 is a high severity stack buffer overflow in Sandboxie-Plus Sandboxie with a CVSS score of 8.8. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Last updated: Jul 24, 2026

Quick answer

Direct answer

CVE-2026-34464 is a high severity stack buffer overflow in Sandboxie-Plus Sandboxie with a CVSS score of 8.8. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Risk scores

CVSS base score
8.8HIGH
EPSS probability
0.15%
Higher than 4 percent of all CVEs
CISA KEV
Not listed
CVSS metricWhat it means
Attack vector (AV:L)Local access needed
Attack complexity (AC:H)High complexity
Attack requirements (AT:P)Attack requirements present
Privileges required (PR:L)Low privileges required
User interaction (UI:N)No user interaction
Confidentiality (VC:H)High confidentiality impact
Integrity (VI:H)High integrity impact
Availability (VA:H)High availability impact

CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

About Sandboxie-Plus Sandboxie

CVE-2026-34464 affects Sandboxie-Plus Sandboxie, a product from Sandboxie-Plus. Before acting, confirm where Sandboxie-Plus Sandboxie runs in your estate, who owns it and whether it is reachable from the internet, because exposure decides real risk more than the score alone.

What the flaw is

In plain terms: 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.

The weakness class is Stack Buffer Overflow. A write past the end of a stack buffer can corrupt control data.

Based on its CVSS vector, the flaw needs local or adjacent access, needs some level of access, and needs no user interaction. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Affected versions and timeline

FieldDetail
ProductSandboxie-Plus Sandboxie
Affected versionsSandboxie before 1.17.3
PublishedMay 5, 2026
Last modifiedJul 24, 2026
Added to CISA KEVNot listed
Assigning CNAsecurity-advisories@github.com

How to detect it

  • Inventory every instance of Sandboxie-Plus Sandboxie and record the running version against the affected range above.
  • Check external attack surface scans for internet facing instances of the component.
  • Review logs on affected systems for unusual requests, errors or new processes around the vulnerable function.
  • Confirm with an authenticated vulnerability scan once your scanner has a check for this CVE.

How to fix it

  • Apply the fixed version of Sandboxie-Plus Sandboxie named in the vendor advisory.
  • If patching must wait, restrict network access to the affected service and put it behind authentication or a web application firewall rule.
  • Rescan after the change to prove the exposure is gone, then close the ticket.

CTEM action plan

CTEM stageWhat to do for this CVE
ScopeAdd every business service that depends on Sandboxie-Plus Sandboxie to the current CTEM cycle.
DiscoverFind all instances, including shadow and cloud deployments, and record versions and exposure.
PrioritizeRank using EPSS and CVSS together with asset exposure and business impact.
ValidateConfirm the flaw is reachable and exploitable in your environment and that compensating controls work.
MobilizeAssign the fix to the asset owner with a due date matched to the priority, then verify closure.

CWE References

Technical References

Frequently asked questions

CVE-2026-34464 is a high severity stack buffer overflow in Sandboxie-Plus Sandboxie with a CVSS score of 8.8. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

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