PatchTheCVECVE-2026-20043: As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco owned Open Source S
CVE-2026-20043 is a critical-severity flaw (CVSS 9.0) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco owned Open Source Snort 3 Software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20043 are related to issues concerning out-of-bounds writes that are grouped under the Common W
Why this priority
- Critical severity
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 9.0 (Critical) |
| Attack vector | Network (remote) |
| Attack complexity | High |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.3% (top 83%) |
| CISA exploited list | No |
| Weakness | CWE-787 |
| Published | 2026-10-21 |
| Last modified | 2026-10-22 |
Last updated 2026-10-22 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Timeline
- Published CVE record published
- Updated Record last modified
Exact fixes by distribution
Advisories and coverage
Official advisories
- INCIBE-CERT Spain: Múltiples vulnerabilidades en productos de Cisco 2026-10-23
- Cisco Security Advisories: Multiple Cisco Products Snort 3 Security Hardening Release: October 2026 2026-10-22
- Cisco Security Advisories: Cisco Advance Notification for Publication of October 21, 2026, Security Advisories 2026-10-21
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-20043?
No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.
Is CVE-2026-20043 being exploited?
CVE-2026-20043 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-20043 affect?
CVE-2026-20043 affects affected software. Severity is critical (CVSS 9.0). As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco owned Open Source Snort 3 Software engineering team has conducted a comprehensive internal security review. This review resulted in software hardenin
How urgent is CVE-2026-20043?
Priority 41/100. Critical severity; Remotely exploitable, no login, no user action