CVE-2026-27749

Published Mar 5, 2026

Last updated 3 days ago

CVSS high 8.5

Overview

Description
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.
Source
disclosure@vulncheck.com
NVD status
Analyzed
Products
internet_security

Risk scores

CVSS 4.0

Type
Secondary
Base score
8.5
Impact score
-
Exploitability score
-
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
Severity
HIGH

CVSS 3.1

Type
Primary
Base score
7.8
Impact score
5.9
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity
HIGH

Weaknesses

disclosure@vulncheck.com
CWE-502

Social media

Hype score
Not currently trending

Configurations

Related CVEs

  1. Avira Internet Security contains a time-of-check time-of-use (TOCTOU) vulnerability in the Optimizer component. A privileged service running as SYSTEM identifies directories for cleanup during a scan phase and subsequently deletes them during a separate cleanup phase without revalidating the target path. A local attacker can replace a previously scanned directory with a junction or reparse point before deletion occurs, causing the privileged process to delete an unintended system location. This may result in deletion of protected files or directories and can lead to local privilege escalation, denial of service, or system integrity compromise depending on the affected target.•CVE-2026-27750
  2. Avira Internet Security contains an improper link resolution vulnerability in the Software Updater component. During the update process, a privileged service running as SYSTEM deletes a file under C:\\ProgramData without validating whether the path resolves through a symbolic link or reparse point. A local attacker can create a malicious link to redirect the delete operation to an arbitrary file, resulting in deletion of attacker-chosen files with SYSTEM privileges. This may lead to local privilege escalation, denial of service, or system integrity compromise depending on the targeted file and operating system configuration.•CVE-2026-27748
  3. A local privilege escalation vulnerability in Bitdefender Total Security 27.0.46.231 allows low-privileged attackers to elevate privileges. The issue arises from bdservicehost.exe deleting files from a user-writable directory (C:\ProgramData\Atc\Feedback) without proper symbolic link validation, enabling arbitrary file deletion. This issue is chained with a file copy operation during network events and a filter driver bypass via DLL injection to achieve arbitrary file copy and code execution as elevated user.•CVE-2025-7073
  4. A vulnerability, which was classified as critical, was found in Comodo Internet Security Premium 12.3.4.8162. Affected is an unknown function of the component File Name Handler. The manipulation of the argument name/folder leads to path traversal. It is possible to launch the attack remotely. The complexity of an attack is rather high. The exploitability is told to be difficult. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.•CVE-2025-7098
  5. A vulnerability, which was classified as critical, has been found in Comodo Internet Security Premium 12.3.4.8162. This issue affects some unknown processing of the file cis_update_x64.xml of the component Manifest File Handler. The manipulation of the argument binary/params leads to os command injection. The attack may be initiated remotely. The complexity of an attack is rather high. The exploitation is known to be difficult. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.•CVE-2025-7097

References

Sources include official advisories and independent security research.