Potential for cross-site scripting in PostHog-js

Description

Impact

Potential for cross-site scripting in posthog-js.

Patches

The problem has been patched in posthog-js version 1.57.2.

Workarounds

  • This isn't an issue for sites that have a Content Security Policy in place.
  • Using the HTML tracking snippet on PostHog Cloud always guarantees the latest version of the library – in that case no action is required to upgrade to the patched version.

References

We will publish details of the vulnerability in 30 days as per our security policy.

Basic information

Type
reviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2023-05-22 20:35:03 UTC
Updated
2023-11-12 05:01:39 UTC
GitHub reviewed
2023-05-22 20:35:03 UTC
NVD published
2023-05-26

EPSS Score

Score Percentile
0.62% 69.86%

CVSS Scores

Base score Version Severity Vector
5.4 3.1
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N 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:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
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:N)
Service keeps running; no real outage angle.

Identifiers

CWEs

CWE id Name
CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Affected packages (1)

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

Ecosystem Package Vulnerable range First patched Vulnerable functions
npm posthog-js < 1.57.2 1.57.2

References

cvelogic Threat Intelligence