CVE-2023-31176Network attack vector

Authentication bypass via guessable session tokens

Published Nov 30, 2023 · Updated Oct 16, 2024

Insufficient entropy in SEL-451 firmware allows remote attackers to brute-force session tokens and bypass authentication. The session mechanism generates tokens with too little entropy, leaving a search space that can be exhaustively guessed through a network interface. No credentials or user interaction are required; a successful guess grants an authenticated session with integrity impact to device operations but no vendor-reported confidentiality or availability impact.

CVSS severity7.5
High
EPSS probability0.93%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insufficient entropy in SEL-451 firmware allows remote attackers to brute-force session tokens and bypass authentication. The session mechanism generates tokens with too little entropy, leaving a search space that can be exhaustively guessed through a network interface. No credentials or user interaction are required; a successful guess grants an authenticated session with integrity impact to device operations but no vendor-reported confidentiality or availability impact.

The record

CVE
CVE-2023-31176
Published
Nov 30, 2023
Updated
Oct 16, 2024
Vendor
Schweitzer Engineering Laboratories
Product
SEL-451 Protection, Automation, and Bay Control System
Classifications
CWE-331, CAPEC-115, T1110
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 30, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=R315-V0 <R315-V4
  2. Affected versionversion=R316-V0 <R316-V4
  3. Affected versionversion=R317-V0 <R317-V4
  4. Affected versionversion=R318-V0 <R318-V5
  5. Affected versionversion=R320-V0 <R320-V3
  6. Affected versionversion=R321-V0 <R321-V3
  7. Affected versionversion=R322-V0 <R322-V3
  8. Affected versionversion=R323-V0 <R323-V5
  9. Affected versionversion=R324-V0 <R324-V4
  10. Affected versionversion=R325-V0 <R325-V3
  11. Affected versionversion=R326-V0 <R326-V1
  12. Affected versionversion=R327-V0 <R327-V1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Schweitzer Engineering Laboratories · SEL-451 Protection, Automation, and Bay Control Systemversion=R315-V0 <R315-V4; version=R316-V0 <R316-V4; version=R317-V0 <R317-V4; version=R318-V0 <R318-V5; version=R320-V0 <R320-V3; version=R321-V0 <R321-V3; version=R322-V0 <R322-V3; version=R323-V0 <R323-V5; version=R324-V0 <R324-V4; version=R325-V0 <R325-V3; version=R326-V0 <R326-V1; version=R327-V0 <R327-V1
Schweitzer Engineering Laboratories · SEL-451 Firmwareversion=R315-V0 <R315-V4; version=R316-V0 <R316-V4; version=R317-V0 <R317-V4; version=R318-V0 <R318-V5; version=R320-V0 <R320-V3; version=R321-V0 <R321-V3; version=R322-V0 <R322-V3; version=R323-V0 <R323-V5; version=R324-V0 <R324-V4; version=R325-V0 <R325-V3; version=R326-V0 <R326-V1; version=R327-V0 <R327-V1

Published CVSS scores

7.5Schweitzer Engineering LaboratoriesCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
9.8NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-331Insufficient Entropy
CAPEC-115Authentication Bypass
T1110Brute Force

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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