Skip to content
Fencer Vulns
medium 5.4

CVE-2023-33962 json

JStachio XSS vulnerability: Unescaped single quotes

published 2023-05-30 3 y ago modified 2026-06-17 4 mo ago also GHSA-gwxv-jv83-6qjr , EUVD-2023-1810

cvss
5.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 47%
public exploits
0
none known

Summary

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 sensitive information, or even the propagation of malware.

Version 1.0.1 contains a patch for this issue. To mitigate this vulnerability, the template engine should properly escape special characters, including single quotes. Common practice is to escape `'` as `&#39`. As a workaround, users can avoid this issue by using only double quotes `"` for HTML attributes.

Patch / fix

  • maven io.jstach:jstachio 1.0.1
  • jstachio_project jstachio 1.0.1

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
21 mo ago

Exploit prediction

0.58% chance of exploitation in the next 30 days, higher than 47% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/jstachio/jstachio/security/advisories/GHSA-gwxv-jv83-6qjr referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
NVD 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
GitHub 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
maven io.jstach:jstachio
<1.0.1
1.0.1

Affected products

  • jstachio jstachio

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.