# CVE-2026-77708: SonicWall SonicOS stack-based buffer overflow in TACACS+ client

Source: https://junglewise.ai/threats/cve-2026-77708-a-pre-authentication-stack-based-buffer-overflow-vulnerability  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-06. Updated: 2026-11-06  
License: CC BY 4.0 with a link back

CVE-2026-77708 · Severity: info · Published 2026-11-06

SonicOS is the operating system for SonicWall network security appliances. A stack-based buffer overflow in the TACACS+ authentication client could allow an unauthenticated attacker to trigger a denial of service, causing the appliance to crash and interrupt network protection.

Technologies: [SonicWall SonicOS](https://junglewise.ai/threats/technologies/sonicos). Vendors: [SonicWall](https://junglewise.ai/threats/vendors/sonicwall).

## Quick answers

**Is CVE-2026-77708 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-77708 being exploited in the wild.

**How severe is CVE-2026-77708?** Informational severity, published 6 November 2026.

**Which products and versions are affected?** SonicWall SonicOS.

**Is there a fix for CVE-2026-77708?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-77708 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-77708?** Check whether you run SonicWall SonicOS. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A pre-authentication stack-based buffer overflow exists in the SonicOS TACACS+ authentication client component. The vulnerability can be triggered remotely without authentication under specific conditions, allowing an attacker to cause an application-level denial of service. This is a memory safety issue in the authentication subsystem.

## Affected products

- SonicWall SonicOS

## Timeline

- 2026-11-06: disclosed

## References

- [https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2026-0014](https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2026-0014)

## Related threats

- [SonicWall SonicOS heap-based buffer overflow in SSL-VPN](https://junglewise.ai/threats/cve-2026-82308-a-pre-authentication-heap-based-buffer-overflow-vulnerability-has)
- [SonicWall SonicOS heap buffer overflow in TACACS+ client](https://junglewise.ai/threats/cve-2026-77709-a-pre-authentication-heap-based-buffer-overflow-vulnerability-has)
- [SonicWall SonicOS SSLVPN SAML authentication bypass](https://junglewise.ai/threats/cve-2026-19868-an-authentication-enforcement-vulnerability-in-sonicos-sslvpn)
- [SonicWall SonicOS weak password hashing](https://junglewise.ai/threats/cve-2026-19703-a-weak-password-hashing-vulnerability-has-been-identified-on)
- [SonicOS permissive cross-domain policy in management interface](https://junglewise.ai/threats/cve-2026-107155-a-permissive-cross-domain-policy-vulnerability-has-been)