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Double FreeWeakness · CWE-415

CVE-2026-20026

MEDIUM · 5.8 CVSS v3.1 Published 2026-01-07
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
67/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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 use-after-free 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 unexpectedly restart the Snort 3 Detection Engine, which could cause a denial of service (DoS).

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A buffer use-after-free vulnerability in Snort 3's DCE/RPC request processing allows an unauthenticated remote attacker to cause information leakage or unexpected restarts of the detection engine via specially crafted DCE/RPC traffic through an inspected connection.

MitigationApply vendor-supplied patches for affected Cisco products running Snort 3; until patched, consider filtering or rate-limiting DCE/RPC traffic at network boundaries to reduce exposure.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Snort 3 installation and version
    Run 'snort3 -V' or check the installed package version via package manager (e.g., 'apt list --installed | grep snort3' or 'rpm -qa | grep snort3')
    Affected if The installed Snort 3 version falls within the affected version range and has not been patched
  2. Locate Snort 3 configuration file
    Common locations: /etc/snort/snort.lua or /usr/local/etc/snort/snort.lua. Search for 'DCE/RPC' or 'dcerpc' in the configuration
    Affected if DCE/RPC preprocessor or inspection is explicitly configured and enabled in snort.lua
  3. Verify DCE/RPC inspection is active
    Check snort.conf or snort.lua for 'dcerpc' or 'DCE_RPC' preprocessor settings. Look for lines like 'dcerpc = { ... }' or ensure DCE/RPC is not commented out
    Affected if The DCE/RPC preprocessor is enabled and not disabled via configuration
  4. Inspect Snort alert and crash logs
    Check /var/log/snort/ (or configured log directory) for alerts tagged with DCE/RPC, and system logs (journalctl, /var/log/messages) for snort process restarts or crashes related to DCE/RPC traffic
    Affected if Recent crashes, restarts, or alerts involving DCE/RPC preprocessor are found in logs
  5. Review active network interfaces with Snort inspection
    Identify which interfaces Snort monitors (e.g., via snort.conf or command-line interface configuration) and determine if those interfaces receive DCE/RPC traffic
    Affected if Snort is actively inspecting an interface that processes DCE/RPC traffic (ports 135, 139, 445, or dynamic RPC endpoints)

The environment is affected if running a vulnerable Snort 3 version with DCE/RPC inspection enabled and actively processing DCE/RPC traffic on inspected network interfaces.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor-supplied patches for affected Cisco products running Snort 3; until patched, consider filtering or rate-limiting DCE/RPC traffic at network boundaries to reduce exposure.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation12.0 h
  • Testing16.0 h
  • Review / QA8.0 h
40.0 hours of engineering $6,800
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-20026 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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