DOM Expressions has a Cross-Site Scripting (XSS) vulnerability due to improper use of string.replace

Description

> [!NOTE]
> This advisory was originally emailed to [email protected] by @nsysean.

To sum it up, the use of javascript's .replace() opens up to potential XSS vulnerabilities with the special replacement patterns beginning with $.

Particularly, when the attributes of Meta tag from solid-meta are user-defined, attackers can utilise the special replacement patterns, either $' or `$`` to achieve XSS.

The solid-meta package has this issue since it uses useAffect and context providers, which injects the used assets in the html header. "dom-expressions" uses .replace() to insert the assets, which is vulnerable to the special replacement patterns listed above.

This effectively means that if the attributes of an asset tag contained user-controlled data, it would be vulnerable to XSS. For instance, there might be meta tags for the open graph protocol in a user profile page, but if attackers set the user query to some payload abusing .replace(), then they could execute arbitrary javascript in the victim's web browser. Moreover, it could be stored and cause more problems.

Basic information

Type
reviewed
Severity
high
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2025-02-25 17:49:57 UTC
Updated
2025-02-25 17:49:59 UTC
GitHub reviewed
2025-02-25 17:49:57 UTC
NVD published
2025-02-21

EPSS Score

Score Percentile
0.34% 56.37%

CVSS Scores

Base score Version Severity Vector
7.3 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.

Identifiers

CWEs

CWE id Name
CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-116 Improper Encoding or Escaping of Output

Credits

  • nsysean (reporter)
  • ryansolid (remediation_developer)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
npm dom-expressions < 0.39.5 0.39.5

References

cvelogic Threat Intelligence