CVE-2023-29453: Templates do not properly consider backticks (`) as Javascript string delimiters, and do not escape them as expected. Backticks are used, since ES6, f...

Description

Templates 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.

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.75%

50.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Zabbix	Zabbix-Agent2	>= 5.0.0, < 5.0.35
Zabbix	Zabbix-Agent2	>= 6.0.0, < 6.0.18
Zabbix	Zabbix-Agent2	>= 6.4.0, < 6.4.3

References

https://support.zabbix.com/browse/ZBX-23388Vendor Advisory
https://support.zabbix.com/browse/ZBX-23388Vendor Advisory

Timeline

Published: Oct 12, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-29453?

Templates 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.

How severe is CVE-2023-29453?

CVE-2023-29453 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.75% probability of exploitation in the next 30 days.

How do I fix CVE-2023-29453?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.