CVE-2023-31176
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 · uneditedAn Insufficient Entropy vulnerability in the Schweitzer Engineering Laboratories SEL-451 could allow an unauthenticated remote attacker to brute-force session tokens and bypass authentication. See product Instruction Manual Appendix A dated 20230830 for more details.
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 confidenceThe SEL-451 protection relay uses insufficient entropy when generating session tokens, creating a predictable and small keyspace that allows attackers to brute-force valid session tokens. This enables unauthenticated remote attackers to bypass authentication entirely and gain administrative access to the device.
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>= r315-v0, < r315-v4>= r316-v0, < r316-v4>= r317-v0, < r317-v4>= r318-v0, < r318-v5>= r320-v0, < r320-v3>= r321-v0, < r321-v3>= r322-v0, < r322-v3>= r323-v0, < r323-v5>= r324-v0, < r324-v4>= r325-v0, < r325-v3= r326-v0= r327-v0CVSS 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
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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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Identify the device modelAccess the device web interface or check the device nameplate/documentation to confirm it is an SEL-451 protection relay.Affected if The device is not an SEL-451 relay, this CVE does not apply.
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Determine the firmware versionLog into the device web interface and navigate to the System > Firmware or About section to view the installed firmware version (e.g., r315-v0, r326-v0).Affected if The firmware version falls within any of these ranges: >= r315-v0 and < r315-v4; >= r316-v0 and < r316-v4; >= r317-v0 and < r317-v4; >= r318-v0 and < r318-v5; >= r320-v0 and < r320-v3; >= r321-v0 and < r321-v3; >= r322-v0 and < r322-v3; >= r323-v0 and < r323-v5; >= r324-v0 and < r324-v4; >= r325-v0
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Verify if web-based management is enabledCheck the device network configuration settings to confirm the embedded web server/HTTPS management interface is enabled and accessible over the network.Affected if The web management interface is disabled, the session token vulnerability cannot be exploited remotely.
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Assess network exposure of the management interfaceReview network firewall rules and access control lists to determine if the device web interface is reachable from untrusted networks or the internet.Affected if The management interface is directly exposed to untrusted networks, an attacker could potentially brute-force session tokens.
If the device is an SEL-451 relay with web management enabled and the firmware version matches any of the affected version ranges listed, the environment is vulnerable to CVE-2023-31176.
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 · scopedContact Schweitzer Engineering Laboratories for firmware updates addressing the entropy weakness; until patched, isolate the device behind strict network controls and monitor for brute-force authentication attempts.
Upgrade to SEL-451 firmware r315-v4, r316-v4, r317-v4, or r318-v5 (or later) depending on your current release branch
- Identify the current firmware version of the SEL-451 device by accessing the device interface or checking the device label
- Navigate to the SEL Support website (selinc.com) and locate the SEL-451 firmware download section
- Download the appropriate fixed firmware version based on your current branch: r315-v4 or higher, r316-v4 or higher, r317-v4 or higher, or r318-v5 or higher
- Review the product Instruction Manual Appendix A (dated 20230830) for detailed firmware upgrade procedures
- Backup the current device configuration before performing the upgrade
- Follow SEL-451 firmware upgrade instructions in the manual to install the fixed firmware version
- Verify the upgrade was successful by confirming the new firmware version in the device interface
- Test authentication functionality to confirm the vulnerability is remediated
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation8.0 h
- Implementation12.0 h
- Testing16.0 h
- Review / QA8.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $12,160.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-31176 — 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-2023-31176 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
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