CVE-2026-20011

mediumpriority · track · 23EPSS 0.005 · 44 %ileNLUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
0.53% (44th) EPSS
CVSS 5.8 · medium
Is it mine?
643 products
Check your exposure
Who says so?
2 sources
cisco_csaf · ncsc_nl

EPSS · scored 2026-10-27

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.

01

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

02

cvss

Technical severity, 0–10. One row per scoring source.

5.8
010

base score 0–10 · higher = more severe · hover a vector to decode

v3.15.8mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Lprimary · psirt@cisco.com USexploitability 3.9 · impact 1.4
v3.15.3mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L/E:Usecondary · CVSS-BT (t0sche)
v3.15.8mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Lsecondary · NCSC-NL NL
v3.15.8mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Lsecondary · Cisco PSIRT US
03

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS
04

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-805USCWE-805USCWE-805US
05

affected products (643)

Products and version ranges known to be affected.

showing 20 of 643
06

advisories (2)

Vendor and ecosystem advisories describing this.

  • NCSC-2026-0450Kwetsbaarheden verholpen in Snort 3 van CiscoNL2026-10-22csaf · ncsc_nlNL

    Cisco heeft meerdere kwetsbaarheden verholpen in Snort 3, het open source intrusion detection en prevention systeem dat in diverse Cisco-producten wordt gebruikt.

  • cisco-sa-snort3-mime-vulns-bkXjcKktMultiple Cisco Products Snort 3 SMTP MIME Denial of Service Vulnerability2026-10-21csaf · cisco_csafUS

    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. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is part of a group of advisories. For a complete list of the advisories and links to them, see Cisco Advance Notification for Publication of October 21, 2026, Security Advisories ["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-notice-QGwHnJ6k"]. In addition, for further documentation of improvements and fixes in Snort 3, see Multiple Cisco Products Snort 3 Security Hardening Release: October 2026 ["https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-snort3-ybgmhTQe"].

07

sources

Which sources assert this record, and when.

cisco_csafncsc_nlNVDCVE.orgMITRE
published 2026-10-21modified 2026-10-22
08

references (1) nvd

External citations — patches, advisories, analysis.

scry

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