CVE-2026-20011 Multiple Cisco Products Snort 3 SMTP MIME Denial of Service Vulnerability
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-20011?
CVE-2026-20011 is a medium-severity vulnerability in Cisco Open Source Snort3, published on 21 Oct 2026.
Official description
Multiple Cisco products are affected by a vulnerability in the Snort 3 SMTP MIME Decoder that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart. This vulnerability is due to a lack of error checking when the MIME fields of the SMTP header are parsed. An attacker could exploit this vulnerability by sending crafted SMTP packets through an established connection to be parsed by Snort 3. A successful exploit could allow the attacker to cause a denial of service (DoS) condition when the Snort 3 Detection Engine unexpectedly restarts.
Weakness: CWE-805
Which versions are affected by CVE-2026-20011?
How do I fix CVE-2026-20011?
No fix has been published for CVE-2026-20011 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-20011 being exploited?
There is no known exploitation of CVE-2026-20011 in the wild and no public exploit code.
Sources
Also known as GHSA-mj78-cj39-7cv9.