CVE-2026-27748
Published: 05 March 2026
Summary
CVE-2026-27748 is a high-severity Link Following (CWE-59) vulnerability in Avira Internet Security. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 8.0th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2026-27748 is an improper link resolution vulnerability (CWE-59) in the Software Updater component of Avira Internet Security. Published on 2026-03-05, it affects the update process where 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. The vulnerability has a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H), indicating high impact potential from local access.
A local attacker with low privileges can exploit this by creating a malicious symbolic link or reparse point that redirects the delete operation to an arbitrary file. This allows deletion of attacker-chosen files using SYSTEM privileges, potentially leading to local privilege escalation, denial of service, or system integrity compromise, depending on the targeted file and operating system configuration.
Mitigation details are referenced in the following advisories: https://support.avira.com/hc/en-us/articles/360010656158-Current-Avira-versions, https://www.avira.com/en/internet-security, and https://www.gendigital.com/us/en/contact-us/security-advisories/.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-9820
Vulnerability details
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…
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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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Vulnerability enables local arbitrary file deletion with SYSTEM privileges via symlink abuse, directly supporting exploitation for privilege escalation (T1068) and indicator removal via targeted file deletion (T1070.004).
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly remediates the improper link resolution flaw in the Software Updater by requiring identification, reporting, and timely correction of the vulnerability.
Requires validation of file paths prior to deletion operations to block resolution through symbolic links or reparse points exploited in this CVE.
Enforces least privilege on the SYSTEM-level updater service to limit the impact of redirected file deletions to non-critical locations.