SuricataApplication · Suricata Ids

CVE-2019-15699

CRITICAL · 9.1 CVSS v3.1 Published 2019-09-24
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
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
An issue was discovered in app-layer-ssl.c in Suricata 4.1.4. Upon receiving a corrupted SSLv3 (TLS 1.2) packet, the parser function TLSDecodeHSHelloExtensions tries to access a memory region that is not allocated, because the expected length of HSHelloExtensions does not match the real length of the HSHelloExtensions part of the packet.

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 · high confidence

In Suricata 4.1.4, the TLSDecodeHSHelloExtensions function in app-layer-ssl.c lacks proper bounds validation when processing SSLv3/TLS 1.2 packets. When a corrupted packet declares an HSHelloExtensions length that doesn't match the actual data available, the parser attempts to read from an unallocated memory region, causing an out-of-bounds read vulnerability.

MitigationUpgrade to Suricata 4.1.5 or later. Alternatively, implement network-level filtering to drop malformed SSL/TLS handshake packets before they reach the Suricata instance.

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

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
SuricataApplication
Affected:= 4.1.4

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
Unchanged
Confidentiality
High
Integrity
None
Availability
High

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

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 Suricata installation and version
    Run `suricata --version` to confirm the installed version of Suricata
    Affected if Version displayed is 4.1.4 exactly
  2. Verify SSL/TLS protocol parsing is enabled
    Check the suricata.yaml configuration file for `app-layer.protocols.tls.enabled` setting (typically in /etc/suricata/suricata.yaml or similar)
    Affected if TLS parsing is set to `enabled: true` or not explicitly disabled
  3. Confirm SSL detection is configured for the expected traffic
    Inspect the `app-layer.protocols.tls.-detection-ports` configuration to see which ports are configured for SSL/TLS inspection
    Affected if Ports are configured and traffic on those ports would reach Suricata (e.g., port 443)

You are affected only if Suricata version 4.1.4 is running AND SSL/TLS protocol parsing is enabled and processing traffic on configured ports.

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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to Suricata 4.1.5 or later. Alternatively, implement network-level filtering to drop malformed SSL/TLS handshake packets before they reach the Suricata instance.

Recommended fix Moderate confidence

Suricata 5.0.x (or latest stable 4.1.x above 4.1.4)

  1. 1. Back up your current Suricata configuration files (e.g., suricata.yaml, classification.config, threshold.config)
  2. 2. Stop the Suricata service
  3. 3. Obtain Suricata 5.0.x or the latest stable 4.1.x release from the official repository (https://suricata.io/download/)
  4. 4. Install the new version following standard upgrade procedures
  5. 5. Restore your configuration files from the backup
  6. 6. Validate configuration syntax: `suricata --test-config`
  7. 7. Start the Suricata service and verify normal operation
  8. 8. Monitor logs for any errors related to SSL/TLS parsing
Caveat Review release notes for deprecation warnings; some rule keywords or output formats may have changed between 4.1.4 and 5.0.x

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Suricata Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing8.0 h
  • Review / QA4.0 h
20.0 hours of engineering $3,440
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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-2019-15699 in production — separate from our analysis above.

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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
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  • Version or environment caveats, and links to real fixes
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