CVE-2026-77708
UnknownSummary
A pre-authentication stack-based buffer overflow vulnerability was identified in the SonicOS TACACS+ authentication client. Under specific conditions it could allow a remote unauthenticated attacker to cause an application-level denial of service.
Risk Assessment
An attacker can, without authentication, make the TACACS+ authentication service unavailable, disrupting access management for network devices. This may hinder infrastructure administration.
Recommendation
Update SonicOS to a patched version and restrict access to the TACACS+ service to trusted authentication servers only.
Other vulnerabilities in SonicOS
See all- CVE-2026-82308Unknown
A pre-authentication heap-based buffer overflow vulnerability was identified in the SonicOS SSL-VPN service. It could allow a remote unauthenticated attacker to cause an application-level denial of service.
- CVE-2026-77709Unknown
A pre-authentication heap-based buffer overflow vulnerability was identified in the SonicOS TACACS+ authentication client. Under specific conditions it could allow a remote unauthenticated attacker to cause an application-level denial of service.
- CVE-2026-19703Unknown
A weak password hashing vulnerability has been identified on SonicOS virtual appliances. Under specific conditions, an attacker with existing local access could disclose a platform credential that grants access to a limited subset of platform settings.
- CVE-2026-107155High
A permissive cross-domain policy vulnerability has been identified in the SonicOS management interface. Under specific conditions it could potentially enable a remote unauthenticated attacker to perform unauthorized operations.
- CVE-2026-107154High
A session validation vulnerability has been identified in the SonicOS management interface. Under specific conditions it could potentially enable a remote unauthenticated attacker to perform unauthorized operations.
- CVE-2026-19868UnknownActively exploited
An authentication enforcement vulnerability in the SonicOS SSLVPN service may allow a user with valid credentials for an alternate authentication method to bypass SAML authentication controls. Successful exploitation may also bypass SAML-enforced multi-factor authentication (MFA).
- CVE-2020-5135CriticalActively exploited
A buffer overflow vulnerability in SonicOS allows a remote attacker to cause a Denial of Service (DoS) and potentially execute arbitrary code by sending a malicious request to the firewall. It affects SonicOS Gen 6 versions 6.5.4.7, 6.5.1.12, 6.0.5.3, SonicOSv 6.5.4.v and Gen 7 version 7.0.0.0.
- CVE-2026-0516Medium
SonicOS contains a vulnerability related to improper neutralization of HTTP headers for scripting syntax. A remote attacker can manipulate the Host header and redirect firewall management users to arbitrary web domains.
- CVE-2026-0206Medium
A post-authentication stack-based buffer overflow vulnerability in SonicOS allows a remote attacker to crash a firewall.
- CVE-2026-0205Medium
A post-authentication path traversal vulnerability in SonicOS allows an attacker to interact with usually restricted services. The attacker must be authenticated to exploit this flaw.
Original NVD description (English source)
A pre-authentication stack-based buffer overflow vulnerability has been identified in the SonicOS TACACS+ authentication client, which in specific conditions could potentially enable a remote unauthenticated attacker to cause an application level denial of service.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS