# CVE-2026-0400: A post-authentication Format String vulnerability in SonicOS allows a remote attacker to crash a firewall.

Source: https://junglewise.ai/threats/cve-2026-0400-a-post-authentication-format-string-vulnerability-in-sonicos  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-02-24  
License: CC BY 4.0 with a link back

CVE-2026-0400 · Severity: medium · CVSS 4.9 · Published 2026-02-24

A post-authentication Format String vulnerability in SonicOS allows a remote attacker to crash a firewall.

Technologies: [SonicWall Nsa 2700](https://junglewise.ai/threats/technologies/nsa-2700), [SonicWall Nsa 2800](https://junglewise.ai/threats/technologies/nsa-2800), [SonicWall Nsa 3700](https://junglewise.ai/threats/technologies/nsa-3700), [SonicWall Nsa 3800](https://junglewise.ai/threats/technologies/nsa-3800), [SonicWall Nsa 4700](https://junglewise.ai/threats/technologies/nsa-4700), [SonicWall Nsa 4800](https://junglewise.ai/threats/technologies/nsa-4800), [SonicWall Nsa 5700](https://junglewise.ai/threats/technologies/nsa-5700), [SonicWall Nsa 5800](https://junglewise.ai/threats/technologies/nsa-5800), [SonicWall Nsa 6700](https://junglewise.ai/threats/technologies/nsa-6700), [SonicWall Nssp 10700](https://junglewise.ai/threats/technologies/nssp-10700), [SonicWall Nssp 11700](https://junglewise.ai/threats/technologies/nssp-11700), [SonicWall Nssp 13700](https://junglewise.ai/threats/technologies/nssp-13700), [SonicWall Nssp 15700](https://junglewise.ai/threats/technologies/nssp-15700), [SonicWall Nsv 270](https://junglewise.ai/threats/technologies/nsv-270), [SonicWall Nsv 470](https://junglewise.ai/threats/technologies/nsv-470), [SonicWall Nsv 870](https://junglewise.ai/threats/technologies/nsv-870), [SonicWall SonicOS](https://junglewise.ai/threats/technologies/sonicos), [SonicWall Tz270](https://junglewise.ai/threats/technologies/tz270), [SonicWall Tz270w](https://junglewise.ai/threats/technologies/tz270w), [SonicWall Tz280](https://junglewise.ai/threats/technologies/tz280), [SonicWall Tz370](https://junglewise.ai/threats/technologies/tz370), [SonicWall Tz370w](https://junglewise.ai/threats/technologies/tz370w), [SonicWall Tz380](https://junglewise.ai/threats/technologies/tz380), [SonicWall Tz470](https://junglewise.ai/threats/technologies/tz470), [SonicWall Tz470w](https://junglewise.ai/threats/technologies/tz470w), [SonicWall Tz480](https://junglewise.ai/threats/technologies/tz480), [SonicWall Tz570](https://junglewise.ai/threats/technologies/tz570), [SonicWall Tz570p](https://junglewise.ai/threats/technologies/tz570p), [SonicWall Tz570w](https://junglewise.ai/threats/technologies/tz570w), [SonicWall Tz580](https://junglewise.ai/threats/technologies/tz580), [SonicWall Tz670](https://junglewise.ai/threats/technologies/tz670), [SonicWall Tz680](https://junglewise.ai/threats/technologies/tz680), [SonicWall Tz80](https://junglewise.ai/threats/technologies/tz80). Vendors: [SonicWall](https://junglewise.ai/threats/vendors/sonicwall).

## Quick answers

**Is CVE-2026-0400 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-0400 being exploited in the wild.

**How severe is CVE-2026-0400?** Medium severity, with a CVSS score of 4.9, published 24 February 2026.

**Which products and versions are affected?** SonicWall Nsa 2700, SonicWall Nsa 2800, SonicWall Nsa 3700, SonicWall Nsa 3800 and 29 more. The advisory does not name versions.

**Is there a fix for CVE-2026-0400?** 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.

**Am I affected by CVE-2026-0400?** Check whether you run SonicWall Nsa 2700, SonicWall Nsa 2800, SonicWall Nsa 3700 or one of the others listed. 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.

## Affected products

- SonicWall Nsa 2700
- SonicWall Nsa 2800
- SonicWall Nsa 3700
- SonicWall Nsa 3800
- SonicWall Nsa 4700
- SonicWall Nsa 4800
- SonicWall Nsa 5700
- SonicWall Nsa 5800
- SonicWall Nsa 6700
- SonicWall Nssp 10700
- SonicWall Nssp 11700
- SonicWall Nssp 13700
- SonicWall Nssp 15700
- SonicWall Nsv 270
- SonicWall Nsv 470
- SonicWall Nsv 870
- SonicWall SonicOS
- SonicWall Tz270
- SonicWall Tz270w
- SonicWall Tz280
- SonicWall Tz370
- SonicWall Tz370w
- SonicWall Tz380
- SonicWall Tz470
- SonicWall Tz470w
- SonicWall Tz480
- SonicWall Tz570
- SonicWall Tz570p
- SonicWall Tz570w
- SonicWall Tz580
- SonicWall Tz670
- SonicWall Tz680
- SonicWall Tz80

## 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 stack-based buffer overflow in TACACS+ client](https://junglewise.ai/threats/cve-2026-77708-a-pre-authentication-stack-based-buffer-overflow-vulnerability)
- [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)