Is CVE-2026-33167 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-33167 being exploited in the wild.

How severe is CVE-2026-33167?

Medium severity, with a CVSS score of 4, published 23 March 2026.

Which products and versions are affected?

actionpack (RubyGems) >= 8.1.0, < 8.1.2.1, ECOSYSTEM:introduced=8.1.0,fixed=8.1.2.1.

Is there a fix for CVE-2026-33167?

Yes. actionpack (RubyGems): upgrade to 8.1.2.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Am I affected by CVE-2026-33167?

Check whether you run actionpack (RubyGems) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-33167: Rails has a possible XSS vulnerability in its Action Pack debug exceptions

Q: Is there a fix for CVE-2026-33167?

Yes. actionpack (RubyGems): upgrade to 8.1.2.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: Am I affected by CVE-2026-33167?

Check whether you run actionpack (RubyGems) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-33167 · Severity: medium · CVSS 4 · Published 2026-03-23

### Impact The debug exceptions page does not properly escape exception messages. A carefully crafted exception message could inject arbitrary HTML and JavaScript into the page, leading to XSS. This affects applications with detailed exception pages enabled (`config.consider_all_requests_local = true`), which is the default in development.

### Releases The fixed releases are available at the normal locations.

### Credit This issue was responsibly reported by Hackerone researcher [fbettag](https://hackerone.com/fbettag).

Technologies: actionpack (RubyGems). Vendors: RubyGems.

Quick answers

Is CVE-2026-33167 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-33167 being exploited in the wild.
How severe is CVE-2026-33167?: Medium severity, with a CVSS score of 4, published 23 March 2026.
Which products and versions are affected?: actionpack (RubyGems) >= 8.1.0, < 8.1.2.1, ECOSYSTEM:introduced=8.1.0,fixed=8.1.2.1.
Is there a fix for CVE-2026-33167?: Yes. actionpack (RubyGems): upgrade to 8.1.2.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2026-33167?: Check whether you run actionpack (RubyGems) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

actionpack (RubyGems): upgrade to 8.1.2.1 or later
```
bundle update actionpack
```

Affected products

actionpack (RubyGems) >= 8.1.0, < 8.1.2.1, ECOSYSTEM:introduced=8.1.0,fixed=8.1.2.1

Identifiers

CVE-2026-33167
GHSA-pgm4-439c-5jp6

References

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