CVE-2026-54900

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: 0.4%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, when in usual mode with create_id enabled, Oj::Parser#parse is vulnerable to heap corruption via a negative-size memcpy. When a JSON object key is exactly 65,535 bytes long, an integer truncation in form_attr (usual.c:63) converts the length to -1 before passing it to memcpy. This causes memcpy to copy SIZE_MAX bytes (interpreted as a huge size_t), corrupting heap memory and crashing the process. The 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
0.4%
EPSS %ILE
36th
KEV
Not listed

Published

June 19, 2026

Last Modified

July 1, 2026

Advisory Details (1)

Auto-updated Jul 1, 2026
🔬 Proof of concept available. Patch available. Sources: github.
githubMentions a patch (unverified)🟡 PoC Available

DFVULN-854: Negative-Size memcpy in Oj::Parser create_id Attribute Handling · Advisory · ohler55/oj · GitHub

https://github.com/ohler55/oj/security/advisories/GHSA-9cv6-qcjw-4grx

Vendor Advisories for CVE-2026-54900(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(2)

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 125 total refreshes for this CVE.

  1. 2026-10-06 15:18 UTCEPSS rescore
  2. 2026-10-05 17:43 UTCEPSS rescore
  3. 2026-10-04 23:22 UTCEPSS rescore
  4. 2026-10-03 14:26 UTCEPSS rescore
  5. 2026-10-02 17:56 UTCEPSS rescore
  6. 2026-10-01 19:50 UTCEPSS rescore
  7. 2026-09-30 15:03 UTCEPSS rescore
  8. 2026-09-29 15:22 UTCEPSS rescore
  9. 2026-09-28 13:51 UTCEPSS rescore
  10. 2026-09-27 13:48 UTCEPSS rescore
  11. 2026-09-26 15:59 UTCEPSS rescore
  12. 2026-09-24 14:04 UTCEPSS rescore
  13. 2026-09-23 17:54 UTCEPSS rescore
  14. 2026-09-20 20:16 UTCEPSS rescore
  15. 2026-09-18 19:28 UTCEPSS rescore
  16. 2026-09-17 19:31 UTCEPSS rescore
  17. 2026-09-16 14:08 UTCEPSS rescore
  18. 2026-09-16 05:15 UTCEPSS rescore
  19. 2026-09-15 03:11 UTCEPSS rescore
  20. 2026-09-13 16:47 UTCEPSS rescore
  21. 2026-09-13 13:07 UTCEG score recompute
  22. 2026-09-11 14:53 UTCEPSS rescore
  23. 2026-09-10 09:35 UTCEPSS rescore
  24. 2026-09-08 22:01 UTCEPSS rescore
  25. 2026-09-07 16:01 UTCEPSS rescore
Show 75 more
  1. 2026-09-06 13:47 UTCEPSS rescore
  2. 2026-09-04 05:06 UTCEPSS rescore
  3. 2026-09-02 14:12 UTCEPSS rescore
  4. 2026-09-01 13:54 UTCEPSS rescore
  5. 2026-09-01 04:40 UTCEPSS rescore
  6. 2026-08-30 20:46 UTCEG score recompute
  7. 2026-08-30 19:17 UTCEPSS rescore
  8. 2026-08-30 01:22 UTCEPSS rescore
  9. 2026-08-28 21:41 UTCEPSS rescore
  10. 2026-08-27 14:25 UTCEPSS rescore
  11. 2026-08-26 14:46 UTCEPSS rescore
  12. 2026-08-25 13:49 UTCEPSS rescore
  13. 2026-08-25 07:08 UTCEG score recompute
  14. 2026-08-24 05:03 UTCEG score recompute
  15. 2026-08-23 00:19 UTCEPSS rescore
  16. 2026-08-22 23:38 UTCEG score recompute
  17. 2026-08-21 23:49 UTCEPSS rescore
  18. 2026-08-21 11:52 UTCEG score recompute
  19. 2026-08-20 22:55 UTCEPSS rescore
  20. 2026-08-20 09:05 UTCEG score recompute
  21. 2026-08-19 17:04 UTCEPSS rescore
  22. 2026-08-19 07:00 UTCEG score recompute
  23. 2026-08-18 13:48 UTCEPSS rescore
  24. 2026-08-17 13:47 UTCEPSS rescore
  25. 2026-08-16 15:19 UTCEG score recompute
  26. 2026-08-16 14:56 UTCEPSS rescore
  27. 2026-08-16 02:14 UTCEPSS rescore
  28. 2026-08-15 13:15 UTCEG score recompute
  29. 2026-08-15 01:30 UTCEPSS rescore
  30. 2026-08-14 11:10 UTCEG score recompute
  31. 2026-08-13 22:00 UTCEPSS rescore
  32. 2026-08-13 09:05 UTCEG score recompute
  33. 2026-08-12 13:51 UTCEPSS rescore
  34. 2026-08-12 06:57 UTCEG score recompute
  35. 2026-08-11 04:52 UTCEG score recompute
  36. 2026-08-11 00:00 UTCEPSS rescore
  37. 2026-08-10 02:47 UTCEG score recompute
  38. 2026-08-09 13:46 UTCEPSS rescore
  39. 2026-08-09 00:43 UTCEG score recompute
  40. 2026-08-08 16:37 UTCEPSS rescore
  41. 2026-08-07 22:38 UTCEG score recompute
  42. 2026-08-06 20:34 UTCEG score recompute
  43. 2026-08-06 13:47 UTCEPSS rescore
  44. 2026-08-05 19:17 UTCEPSS rescore
  45. 2026-08-04 16:25 UTCEG score recompute
  46. 2026-08-04 15:10 UTCEPSS rescore
  47. 2026-08-04 10:39 UTCEPSS rescore
  48. 2026-08-03 14:20 UTCEG score recompute
  49. 2026-08-03 10:36 UTCEPSS rescore
  50. 2026-08-02 09:54 UTCEG score recompute
  51. 2026-08-02 02:27 UTCEPSS rescore
  52. 2026-08-01 07:50 UTCEG score recompute
  53. 2026-08-01 04:16 UTCEPSS rescore
  54. 2026-07-31 05:45 UTCEG score recompute
  55. 2026-07-30 16:28 UTCEPSS rescore
  56. 2026-07-30 03:40 UTCEG score recompute
  57. 2026-07-30 01:30 UTCEPSS rescore
  58. 2026-07-29 01:33 UTCEG score recompute
  59. 2026-07-28 15:37 UTCEPSS rescore
  60. 2026-07-27 21:20 UTCEG score recompute
  61. 2026-07-26 16:47 UTCEG score recompute
  62. 2026-07-26 14:54 UTCEPSS rescore
  63. 2026-07-25 14:18 UTCEPSS rescore
  64. 2026-07-24 14:18 UTCEPSS rescore
  65. 2026-07-23 14:18 UTCEPSS rescore
  66. 2026-07-23 03:20 UTCEG score recompute
  67. 2026-07-22 14:08 UTCEPSS rescore
  68. 2026-07-21 15:25 UTCEPSS rescore
  69. 2026-07-20 17:08 UTCEPSS rescore
  70. 2026-07-19 02:29 UTCEPSS rescore
  71. 2026-07-18 10:04 UTCEPSS rescore
  72. 2026-07-16 17:03 UTCEPSS rescore
  73. 2026-07-15 16:57 UTCEPSS rescore
  74. 2026-07-15 16:57 UTCEPSS rescore
  75. 2026-07-15 02:00 UTCEPSS rescore

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-54900?
CVE-2026-54900 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, when in usual mode with createid enabled, Oj::Parser#parse is vulnerable to heap corruption via a negative-size memcpy. When a JSON object key is exactly 65,535 bytes long, an integer…
When was CVE-2026-54900 disclosed?
CVE-2026-54900 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-2026-54900 actively exploited?
CVE-2026-54900 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (36th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-54900?
CVE-2026-54900 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-2026-54900?
A fix for CVE-2026-54900 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-54900 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-54900

Explore →

Is Your Infrastructure Affected by CVE-2026-54900?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Book a Demo →Browse All CVEs