CVE-2021-37759
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 · uneditedA Session ID leak in the DEBUG log file in Graylog before 4.1.2 allows attackers to escalate privileges (to the access level of the leaked session ID).
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 confidenceGraylog versions before 4.1.2 write session IDs to DEBUG log files. An attacker with access to these logs can extract the leaked session ID and use it to authenticate as that user, effectively hijacking their session and escalating privileges to the access level of the compromised account.
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>= 0.20.0, < 4.1.2CVSS 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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Determine installed Graylog versionRun `graylog-server --version` or check the Graylog web interface under System > Nodes, or inspect the RPM/DEB package version if installed via package managerAffected if version is 0.20.0 or higher but lower than 4.1.2
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Verify DEBUG logging is enabledCheck Graylog configuration file (graylog.conf) for the setting `log_level = DEBUG` or review logging configuration in the web interface under System > LoggingAffected if DEBUG log level is active, causing session IDs to be written to log files
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Inspect log files for session ID leakageExamine Graylog server log files (typically in /var/log/graylog-server/ or the directory specified in log configuration) for occurrences of session identifiers. Search for patterns matching session ID formats (alphanumeric strings of 32+ characters) in DEBUG level entriesAffected if Log files contain DEBUG entries with visible session IDs that could be extracted by an attacker with log access
You are affected if you are running Graylog version 0.20.0 through 4.1.1 with DEBUG logging enabled and log files contain session identifiers in the output.
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 · scoped4.1.2
Upgrade to Graylog 4.1.2 or later, which removes session IDs from DEBUG log output. Until then, restrict access to log files and monitor for unauthorized access.
4.1.2
- Back up your Graylog configuration and database before upgrading
- Stop the Graylog service
- Upgrade Graylog to version 4.1.2 or later
- Verify the upgrade was successful by checking that DEBUG logs no longer contain session IDs
- Restart the Graylog service
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-37759 — 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-2021-37759 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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- Version or environment caveats, and links to real fixes
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