CVE-2023-29453
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 · uneditedTemplates do not properly consider backticks (`) as Javascript string delimiters, and do not escape them as expected. Backticks are used, since ES6, for JS template literals. If a template contains a Go template action within a Javascript template literal, the contents of the action can be used to terminate the literal, injecting arbitrary Javascript code into the Go template. As ES6 template literals are rather complex, and themselves can do string interpolation, the decision was made to simply disallow Go template actions from being used inside of them (e.g., "var a = {{.}}"), since there is no obviously safe way to allow this behavior. This takes the same approach as github.com/google/safehtml. With fix, Template. Parse returns an Error when it encounters templates like this, with an ErrorCode of value 12. This ErrorCode is currently unexported but will be exported in the release of Go 1.21. Users who rely on the previous behavior can re-enable it using the GODEBUG flag jstmpllitinterp=1, with the caveat that backticks will now be escaped. This should be used with caution.
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 confidenceGo's html/template package fails to escape backticks (`) used in ES6 JavaScript template literals, allowing arbitrary JavaScript injection when Go template actions appear inside template literals (e.g., 'var a = {{.}}'). The template action can terminate the JS literal and inject malicious code.
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>= 5.0.0, < 5.0.35>= 6.0.0, < 6.0.18>= 6.4.0, < 6.4.3CVSS 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.
-
Confirm Zabbix Agent2 is installedRun command: which zabbix_agent2 or systemctl list-units | grep zabbix_agent2Affected if Zabbix Agent2 is not installed, then not affected by this specific CVE which targets Zabbix Agent2
-
Check installed Zabbix Agent2 versionRun command: zabbix_agent2 --version or rpm -q zabbix-agent2 (RHEL) or dpkg -l zabbix-agent2 (Debian)Affected if Version falls within ranges: 5.0.0-5.0.34, 6.0.0-6.0.17, or 6.4.0-6.4.2
-
Locate Zabbix custom templates and scriptsSearch for .yaml, .yml, .conf, or template files in /etc/zabbix/zabbix_agentd.d/ and /var/lib/zabbix/ directoriesAffected if Custom templates or user-defined scripts exist that extend default Zabbix monitoring
-
Identify Go template actions inside JavaScript template literalsSearch template files for pattern: backtick character followed by {{.}} or {{`...`}} or other Go template actions. Use grep with pattern: '`.*{{' across template directoriesAffected if Templates contain Go template actions ({{.}}, {{range .}}, etc.) appearing inside JavaScript template literal strings delimited by backticks (`)
-
Verify if Zabbix uses Go-based web frontend or APICheck if Zabbix Server frontend is running and inspect any custom Go templates used by the web interfaceAffected if Custom Go html/template patterns are used in web monitoring templates with ES6 template literal syntax
User is affected if Zabbix Agent2 version is in the affected ranges AND custom templates or scripts contain Go template actions inside JavaScript backtick template literals.
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 · scoped5.0.356.0.186.4.3
Upgrade to Go 1.21+ where Template.Parse returns an error for these patterns, or audit code for vulnerable Go template actions inside JavaScript template literals and restructure/escape appropriately.
Zabbix Agent2 5.0.35, 6.0.18, or 6.4.3 (depending on your current major version branch)
- 1. Identify the currently installed Zabbix Agent2 version using: zabbix_agent2 --version or systemctl status zabbix-agent2
- 2. Based on your current major version, plan the upgrade to the fixed release: For Zabbix 5.0.x, upgrade to 5.0.35 or later; For Zabbix 6.0.x, upgrade to 6.0.18 or later; For Zabbix 6.4.x, upgrade to 6.4.3 or later
- 3. Backup the Zabbix Agent2 configuration file (typically /etc/zabbix/zabbix_agent2.conf)
- 4. Stop the Zabbix Agent2 service: systemctl stop zabbix-agent2
- 5. Upgrade Zabbix Agent2 using your package manager (e.g., yum update zabbix-agent2, apt-get install zabbix-agent2, or dnf update zabbix-agent2)
- 6. Verify the new version is installed: zabbix_agent2 --version
- 7. Start the Zabbix Agent2 service: systemctl start zabbix-agent2
- 8. Verify the service is running correctly: systemctl status zabbix-agent2
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 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 $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-29453 — 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-2023-29453 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- 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