Vulnerability Report

CVE-2026-27749

RCE

Title: Deserialization of Untrusted Data in Avira Internet Security System Speedup

RCE

Proof Of Concept

No public PoC currently indexed for CVE-2026-27749.

CWE Category CWE-502
Published Date Mar 05, 2026
Modified Date Apr 01, 2026
Exploit Status Not Found
Score 7.8 CVSS v4.0
Exploit Probability (EPSS)
0.32%

Vulnerability Summary

CVE-2026-27749: Avira Internet Security contains a deserialization of untrusted data vulnerability in the System Speedup component. The Avira.SystemSpeedup.RealTimeOptimizer.exe process, which runs with SYSTEM privileges, deserializes data from a file located in C:\\ProgramData using .NET BinaryFormatter without implementing input validation or deserialization safeguards. Because the file can be created or modified by a local user in default configurations, an attacker can supply a crafted serialized payload that is deserialized by the privileged process, resulting in arbitrary code execution as SYSTEM.

Impacted Vendors

F
f-secure 1
A
avira 1

Reference Links

https://blog.quarkslab.com/avira-deserialize-delete-and-escalate-the-proper-way-to-use-an-av.html https://support.avira.com/hc/en-us/articles/360010656158-Current-Avira-versions https://www.avira.com/en/internet-security https://www.vulncheck.com/advisories/avira-internet-security-system-speedup-insecure-deserialization
CVSS v4.0
Source Entity [email protected]
Severity HIGH
8.5
Attack Vector
LOCAL
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
N/A
RAW VECTOR CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/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
CVSS v3.1
Source Entity [email protected]
Severity HIGH
7.8
Attack Vector
LOCAL
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS v3.1
Source Entity [email protected]
Severity HIGH
7.8
Attack Vector
LOCAL
Complexity
LOW
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-27749 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector LOCAL
Complexity LOW
Privileges N/A
Interaction NONE
CVSS Vector String CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/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

Affected Stack

No specific products linked.