Action Pack is a Rubygem for building web applications on the Rails framework. In versions on the 8.1 branch prior to 8.1.2.1, 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. Version 8.1.2.1 contains a patch.
CVE-2026-33167
LOWPre-NVD 1.31.3
EchelonGraph scoreLOW confidence
This low-severity CVE scores 1.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: secondary
1.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 1.3Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 1.3
- EG Score
- 1.3(low)
- EG Risk
- 10(Track)EG Risk 10/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity13% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 33%
- KEV
- Not listed
Published
March 23, 2026
Last Modified
June 17, 2026
References (3)
- security-advisories@githubhttps://github.com/rails/rails/commit/6752711c8c31d79ba50d13af6a6698a3b85415e0
- security-advisories@githubhttps://github.com/rails/rails/releases/tag/v8.1.2.1
- security-advisories@githubhttps://github.com/rails/rails/security/advisories/GHSA-pgm4-439c-5jp6
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 4× in last 7d / 4× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-08-01 04:16 UTCEPSS rescore
- 2026-07-30 16:28 UTCEPSS rescore
- 2026-07-30 01:30 UTCEPSS rescore
- 2026-07-27 14:31 UTCEG score recompute
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-33167?
CVE-2026-33167 is a low vulnerability published on March 23, 2026. Action Pack is a Rubygem for building web applications on the Rails framework. In versions on the 8.1 branch prior to 8.1.2.1, the debug exceptions page does not properly escape exception messages. A carefully crafted exception message could inject arbitrary HTML and JavaScript into the page,…
When was CVE-2026-33167 disclosed?
CVE-2026-33167 was first published in the National Vulnerability Database on March 23, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-33167 actively exploited?
CVE-2026-33167 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 67.1% of all scored CVEs.
What is the CVSS score of CVE-2026-33167?
CVE-2026-33167 has a CVSS v3 base score of 1.3 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-33167?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-33167, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-33167
Is Your Infrastructure Affected by CVE-2026-33167?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.