CVE Intelligence
Medium Info disclosure

CVE-2026-20027 — Cisco Snort DCERPC Stub Data Out of Bounds Read

Multiple Cisco products are affected by a vulnerability in the processing of DCE/RPC requests that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to leak sensitive information or to restart, resulting in an interruption of packet inspection. This vulnerability is due to an error in buffer handling logic when processing DCE/RPC requests, which can result in a buffer out-of-bounds read. An attacker could exploit this vulnerability by sending a large number of DCE/RPC requests through an established connection that is inspected by Snort 3. A successful exploit could allow the attacker to obtain sensitive information in the Snort 3 data stream.

Published Jan 7, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: cisco

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.6% (30-day exploitation probability)+7
  • Technical severity (medium)+3
  • Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.6%
ahead of 47% of scored CVEs · Oct 15, 2026
Affects
Cisco
Cisco Secure Firewall Threat Defense (FTD) Software and 1 more
CVSS base
5.3
Medium · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
None
none · proof-of-concept · active
Automatable
Yes
can an attacker script the kill-chain steps
Technical impact
Partial
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Cisco Cisco Secure Firewall Threat Defense (FTD) Software, Cisco Cisco UTD SNORT IPS Engine Software).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Search available logs for exploit probes matching the vulnerability class (info disclosure), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Cisco Cisco Secure Firewall Threat Defense (FTD) Software version 7.0.0version 7.0.0.1version 7.0.1version 7.1.0version 7.0.1.1version 7.1.0.1version 7.0.2version 7.2.0
and 49 more version 7.0.2.1version 7.0.3version 7.1.0.2version 7.2.0.1version 7.0.4version 7.2.1version 7.0.5version 7.3.0version 7.2.2version 7.2.3version 7.3.1version 7.1.0.3version 7.2.4version 7.0.6version 7.2.5version 7.2.4.1version 7.3.1.1version 7.4.0version 7.0.6.1version 7.2.5.1version 7.4.1version 7.2.6version 7.0.6.2version 7.4.1.1version 7.2.7version 7.2.5.2version 7.3.1.2version 7.2.8version 7.6.0version 7.4.2version 7.2.8.1version 7.0.6.3version 7.4.2.1version 7.2.9version 7.0.7version 7.7.0version 7.4.2.2version 7.2.10version 7.6.1version 7.4.2.3version 7.0.8version 7.6.2version 7.7.10version 7.0.8.1version 7.6.2.1version 7.7.10.1version 7.4.2.4version 7.2.10.2version 7.4.3
Vulnerable CVE Program (cve.org) e CISA ADP
Cisco Cisco UTD SNORT IPS Engine Software version 3.17.1Sversion 16.12.3version Fuji-16.9.5version 16.12.4version 17.3.1aversion 16.6.6version 16.12.2version Fuji-16.9.6
and 95 more version 3.17.0Sversion Fuji-16.9.3version Denali-16.3.7version Fuji-16.9.2version Fuji-16.9.4version Everest-16.6.4version Everest-16.6.3version 16.6.5version Denali-16.3.5version 17.2.1rversion 17.1.1version Everest-16.6.2version 16.6.7aversion Denali-16.3.4version 16.6.1version Denali-16.3.9version Denali-16.3.3version 16.12.1aversion 17.3.2version 17.4.1aversion 16.12.5version 17.5.1version Fuji-16.9.7version 16.6.9version 17.3.3version 17.5.1aversion 17.3.4version 17.3.4aversion 17.4.2version 17.4.1bversion 17.6.1aversion 16.6.10version 17.7.1aversion 16.12.6version Fuji-16.9.8version 17.6.2version 17.8.1aversion 16.12.7version 17.3.5version 17.6.3version 17.6.3aversion 17.7.2version 17.9.1aversion 17.6.4version 17.10.1aversion 17.3.6version 16.12.8version 17.3.7version 17.9.2aversion 17.12.5bversion 17.12.4aversion 17.15.2cversion 17.9.5fversion 17.12.4bversion 17.15.2aversion 17.12.5version 17.17.1version 17.12.5aversion 17.9.7aversion 17.15.3aversion 17.15.3version 17.9.5eversion 17.12.5cversion 17.15.4version 17.9.7bversion 17.18.1version 17.18.1aversion 17.12.6version 17.9.8version 17.15.4cversion 17.12.5dversion 17.18.2version 17.9.5aversion 17.11.1aversion 17.9.3aversion 17.12.1aversion 17.9.4version 17.6.6version 17.3.8version 17.3.8aversion 17.6.6aversion 17.9.4aversion 17.12.2version 17.13.1aversion 17.6.5version 17.12.3version 17.6.7version 17.14.1aversion 17.12.4version 17.12.3aversion 17.15.1aversion 17.6.8version 17.9.6version 17.6.8aversion 17.16.1a
Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
5.3 CVSS 3.1 Medium 3.9 1.4 psirt@cisco.com via NIST National Vulnerability Database
5.3 CVSS 3.1 Medium — — cisco via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N (score shown at the top: psirt@cisco.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-200 · Exposure of Sensitive Information

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 0.60%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Look for anomalous data read/export volumes and access to sensitive records.
web/proxy/WAF logsnetwork IDS/IPSapplication logsauthentication logs

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · cisco/cisco secure firewall threat defense (ftd) software, cisco/cisco utd snort ips engine software
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • CVSS changed · 5.3
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Deferred
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVE published
    Jan 7, 2026 · cisco

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

1 on the record

Elsewhere on this site

Cisco
every CVE for this vendor
Info disclosure
same class
CWE-200
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-20336 Cisco Secure Adaptive Security Appliance Software, Secure Firewall Threat Defense Software and Secure Firewall Management Center Software Hardening Release - Resource Lifetime Management Vulnerabilities 29d
  • CVE-2026-20335 Cisco Secure Adaptive Security Appliance Software, Secure Firewall Threat Defense Software and Secure Firewall Management Center Software Hardening Release - Incorrect Calculation Vulnerabilities 29d
  • CVE-2026-20323 Cisco Secure Firewall Management Center and Secure Firewall Threat Defense Software sftunnel Unauthorized Authentication Bypass Vulnerability 29d
  • CVE-2026-20332 Cisco Secure Adaptive Security Appliance Software, Secure Firewall Threat Defense Software and Secure Firewall Management Center Software Hardening Release - Improper Access Control Vulnerabilities 29d
  • CVE-2026-20333 Cisco Secure Adaptive Security Appliance Software, Secure Firewall Threat Defense Software and Secure Firewall Management Center Software Hardening Release - Incorrect Comparison Vulnerabilities 29d
  • CVE-2026-20334 Cisco Secure Adaptive Security Appliance Software, Secure Firewall Threat Defense Software and Secure Firewall Management Center Software Hardening Release - Coding Standards Vulnerabilities 29d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-20027 is "Cisco Snort DCERPC Stub Data Out of Bounds Read", rated Medium. It affects Cisco Secure Firewall Threat Defense (FTD) Software (Cisco); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.3 describes technical severity. EPSS 0.60% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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