A post-authentication Format String vulnerability in SonicOS allows a remote attacker to crash a firewall.
CVE-2026-0400
MEDIUMPre-NVD 4.94.9—Trending — 3 sources updated this week
EchelonGraph scoreMEDIUM confidence
Score 4.9 from GitHub Security Advisory published 2026-02-24. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 4.9; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, ghsa
4.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.9Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 4.9
- EG Score
- 4.9(medium)
- EG Risk
- 27(Track)EG Risk 27/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity49% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 35%
- KEV
- Not listed
Published
February 24, 2026
Last Modified
June 17, 2026
References (1)
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 3× in last 7d / 3× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-27 14:13 UTCEPSS rescore
- 2026-07-27 14:09 UTCEG score recompute
- 2026-07-27 14:09 UTCGHSA enrichment
Related CVEs(same CWE)
Same CWE
10 shownCWE-134
- CVE-2008-7228EG 10.0HIGH
- CVE-2009-1210EG 10.0EPSS p96HIGH
- CVE-2008-6520EG 10.0EPSS p91HIGH
- CVE-2008-6519EG 10.0EPSS p92HIGH
- CVE-2008-5982EG 10.0EPSS p94HIGH
- CVE-2008-3533EG 10.0EPSS p97HIGH
- CVE-2008-3116EG 10.0EPSS p92HIGH
- CVE-2008-0764EG 10.0EPSS p94HIGH
- CVE-2007-5561EG 10.0EPSS p94HIGH
- CVE-2007-1006EG 10.0HIGH
Frequently asked(5)
What is CVE-2026-0400?
CVE-2026-0400 is a medium vulnerability published on February 24, 2026. A post-authentication Format String vulnerability in SonicOS allows a remote attacker to crash a firewall.
When was CVE-2026-0400 disclosed?
CVE-2026-0400 was first published in the National Vulnerability Database on February 24, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-0400 actively exploited?
CVE-2026-0400 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 65.2% of all scored CVEs.
What is the CVSS score of CVE-2026-0400?
CVE-2026-0400 has a CVSS v3.1 base score of 4.9 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-0400?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-0400, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-0400
Is Your Infrastructure Affected by CVE-2026-0400?
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