CVE-2026-31934
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 · uneditedSuricata is a network IDS, IPS and NSM engine. From version 8.0.0 to before version 8.0.4, there is a quadratic complexity issue when searching for URLs in mime encoded messages over SMTP leading to a performance impact. This issue has been patched in version 8.0.4.
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 confidenceSuricata versions 8.0.0 through 8.0.3 contain a quadratic complexity vulnerability in the URL searching functionality for MIME-encoded SMTP messages. The inefficient algorithm causes processing time to scale quadratically with input size, leading to significant performance degradation that could be exploited for denial-of-service.
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>= 8.0.0, < 8.0.4CVSS 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
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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 checksWork through these to decide whether this CVE applies to you.
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Verify Suricata is installed and get its versionRun 'suricata --version' or check the package manager (dpkg -l suricata, rpm -qi suricata)Affected if The version is 8.0.0, 8.0.1, 8.0.2, or 8.0.3
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Confirm SMTP parsing is enabled in Suricata configurationInspect suricata.yaml for 'app-layer:' and 'smtp:' sections, looking for 'enabled: yes' under the SMTP protocol settingsAffected if SMTP protocol parsing is explicitly enabled in the configuration
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Check if MIME inspection is active for SMTPLook for 'mime:' or 'decode-mime:' settings within the SMTP configuration section in suricata.yamlAffected if MIME decoding for SMTP messages is turned on (this is often enabled by default for SMTP inspection)
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Identify if Suricata is processing SMTP trafficReview Suricata logs (eve.json) for 'smtp' events or check if the interface is capturing SMTP traffic on port 25Affected if Suricata is actively parsing SMTP sessions, which would trigger the vulnerable code path
You are affected only if you have Suricata 8.0.0-8.0.3 installed AND SMTP protocol inspection with MIME parsing is enabled and actively processing traffic.
Generated from the published advisory. Verify against your own configuration.
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 · scoped8.0.4
Upgrade Suricata to version 8.0.4 or later to obtain the patch that fixes the quadratic complexity issue in MIME URL parsing.
8.0.4
- 1. Backup current Suricata configuration files and any custom rules
- 2. Download Suricata version 8.0.4 from the official repository (e.g., https://suricata.io/download/)
- 3. Stop the Suricata service
- 4. Install version 8.0.4 using the appropriate package manager or compilation method for your system
- 5. Restore your configuration files if needed
- 6. Verify the installation by checking `suricata --version`
- 7. Start the Suricata service
- 8. Monitor logs to ensure normal operation
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation3.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-31934 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-31934 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data