CVE-2026-54901

MEDIUMPre-NVD 6.36.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 64% of all CVEs by exploit prediction. 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: epss, secondary
6.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 6.3Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.2, Oj::Parser in usual mode does not mark array_class and hash_class references during garbage collection, leading to Use-After-Free. If GC runs after the class is assigned but before a parse, the class object is reclaimed, leaving the parser holding a dangling VALUE. The subsequent parse call dereferences the freed object, producing a segfault. This issue has been fixed in version 3.17.2.

CVSS v3
6.3
EG Score
6.3MEDIUMmedium confidence
EG Risk
33
EG Risk 33/100

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 computed
Severity63% × 45%
Exploitation0% × 40%
Automatability30% × 15%
EPSS PROB
0.3%
EPSS %ILE
24th
KEV
Not listed

Published

June 19, 2026

Last Modified

July 1, 2026

Advisory Details (1)

Auto-updated Jul 1, 2026
Patch available. Sources: github.
githubMentions a patch (unverified)

DFVULN-855: Use-After-Free in Oj::Parser array_class/hash_class GC Marking · Advisory · ohler55/oj · GitHub

https://github.com/ohler55/oj/security/advisories/GHSA-vwm4-62gf-x745

Vendor Advisories for CVE-2026-54901(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(5 across 5 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
ruby-oj3.11.0-1 ... 3.17.4-1 (26 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
ruby-oj3.14.2-1
  • every version up to 3.14.2-1+deb12u1: fixed in 3.14.2-1+deb12u1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
ruby-oj3.16.3-1
  • every version up to 3.16.3-1+deb13u1: fixed in 3.16.3-1+deb13u1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
ruby-oj3.16.12-1 ... 3.17.1-1 (6 versions)
  • every version up to 3.17.3-1: fixed in 3.17.3-1
—
RubyGems(1)
PackageVulnerable rangeFix by version rangeDependents
oj0.5 ... 3.9.2 (294 versions)
  • every version up to 3.17.3: fixed in 3.17.3
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 6× in last 7d / 24× 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.

Showing the most recent 100 of 128 total refreshes for this CVE.

  1. 2026-10-06 15:18 UTCEPSS rescore
  2. 2026-10-05 17:43 UTCEPSS rescore
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  1. 2026-09-06 13:47 UTCEPSS rescore
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  74. 2026-07-18 10:04 UTCEPSS rescore
  75. 2026-07-16 17:03 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2026-54901?
CVE-2026-54901 is a medium vulnerability published on June 19, 2026. Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.2, Oj::Parser in usual mode does not mark arrayclass and hashclass references during garbage collection, leading to Use-After-Free. If GC runs after the class is assigned but before a parse,…
When was CVE-2026-54901 disclosed?
CVE-2026-54901 was first published on June 19, 2026, with the most recent update on July 1, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-54901 actively exploited?
CVE-2026-54901 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (24th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-54901?
CVE-2026-54901 has a CVSS base score of 6.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-54901?
A fix for CVE-2026-54901 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-54901 are linked in the Vendor Advisories panel on this page.

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