CVE-2023-33962: JStachio is a type-safe Java Mustache templating engine

Q: How do I fix CVE-2023-33962?

jstachio: upgrade to 1.0.1. Exact commands for each OS are on this page.

Q: Is CVE-2023-33962 being exploited?

CVE-2023-33962 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2023-33962 affect?

CVE-2023-33962 affects jstachio. Severity is medium (CVSS 5.4). JStachio is a type-safe Java Mustache templating engine. Prior to version 1.0.1, JStachio fails to escape single quotes `'` in HTML, allowing an attacker to inject malicious code. This vulnerability can be exploited by an attacker to execu

Q: How urgent is CVE-2023-33962?

Priority 36/100. Public exploit reference

Routine

MEDIUM 5.4UPGRADE

CVE-2023-33962 is a medium-severity flaw (CVSS 5.4) affecting jstachio. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

JStachio is a type-safe Java Mustache templating engine. Prior to version 1.0.1, JStachio fails to escape single quotes `'` in HTML, allowing an attacker to inject malicious code. This vulnerability can be exploited by an attacker to execute arbitrary JavaScript code in the context of other users visiting pages that use this template engine. This can lead to various consequences, including session hijacking, defacement of web pages, theft of sen

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.6% (top 52%)
CISA exploited list	No
Weakness	CWE-79
Published	2023-05-30
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: jstachio project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-05-30 22:15 UTCPublished CVE record published
2026-06-17 06:02 UTCUpdated Record last modified

jstachio project jstachio UPGRADE

Affected: < 1.0.1

Fixed in: 1.0.1

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy jstachio || rpm -q jstachio || jstachio --version

2. UPGRADE to 1.0.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade jstachio

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade jstachio

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-33962?

jstachio: upgrade to 1.0.1. Exact commands for each OS are on this page.

Is CVE-2023-33962 being exploited?

CVE-2023-33962 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-33962 affect?

CVE-2023-33962 affects jstachio. Severity is medium (CVSS 5.4). JStachio is a type-safe Java Mustache templating engine. Prior to version 1.0.1, JStachio fails to escape single quotes `'` in HTML, allowing an attacker to inject malicious code. This vulnerability can be exploited by an attacker to execu

How urgent is CVE-2023-33962?

Priority 36/100. Public exploit reference

Software pages

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References

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