HeronApplication · Apache
CVE-2021-42010
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 · uneditedHeron versions <= 0.20.4-incubating allows CRLF log injection because of the lack of escaping in the log statements. Please update to version 0.20.5-incubating which addresses this issue.
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 confidenceHeron versions 0.20.4 and earlier contain a CRLF injection vulnerability in logging functionality due to improper escaping of user-controlled input in log statements. Attackers can inject carriage return/line feed characters to manipulate log entries, potentially enabling log poisoning, log splitting, or in some cases HTTP response splitting if logs are reflected in web responses.
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
HeronApplication
< 0.20.5-incubatingCVSS 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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Check Apache Heron installed versionRun 'heron version' or check the Heron installation directory for version information. Common paths include /usr/local/heron or the directory where Heron was extracted.Affected if The installed version is 0.20.4 or earlier (anything less than 0.20.5-incubating).
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Identify log configuration filesLocate Heron's logging configuration files, typically in conf/logging.yml or conf/log4j.properties within the Heron installation directory.Affected if User-controlled input is being written to logs without sanitization - this requires reviewing log statements in Heron topology code or configuration.
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Check if logs are exposed via web UIInspect Heron's tracker or UI configuration files (typically in conf/*.yaml) to determine if log output is served through HTTP endpoints.Affected if Logs are configured to be accessible through web interfaces and user input can be injected into log entries.
If Heron version is less than 0.20.5-incubating AND user-controlled input flows into log statements, the environment is vulnerable to CRLF injection.
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 · scoped0.20.5-incubating
Upgrade Heron to version 0.20.5-incubating or later, which includes proper escaping in log statements to prevent CRLF injection.
0.20.5-incubating
- Download Heron version 0.20.5-incubating from the official Apache Heron releases
- Stop any running Heron instances
- Backup existing configuration and data if needed
- Install or upgrade to Heron version 0.20.5-incubating
- Restart Heron services with the new version
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Heron
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,848.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-42010 — 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-2021-42010 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
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