CVE-2026-71847

HIGHPre-NVD 8.78.7—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 83% 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
Elevated
8.7EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.7Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Ruby JSON is a JSON implementation for Ruby. From 2.20.0 until 2.21.2, Ruby's JSON native C extension clears the consumed JSON::ResumableParser input buffer but leaves state.start, state.cursor, and state.end pointing into released storage. When partial_value reconstructs an incomplete object containing duplicate keys, the duplicate-key warning path calls cursor_position, which dereferences those stale pointers. This results in a heap-use-after-free and can terminate the Ruby process. An attacker who can supply JSON stream data to an application using JSON::ResumableParser may cause process termination when the application calls partial_value on incomplete attacker-controlled input containing duplicate object keys. This issue has been fixed in version 2.21.2.

CVSS v3
8.7
EG Score
8.7(medium)
EG Risk
70(Attend)
EG Risk 70/100SSVC: Attend

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
Severity87% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
17%
KEV
Not listed

Published

August 7, 2026

Last Modified

August 7, 2026

Advisory Details (1)

Auto-updated Aug 7, 2026
🔬 Proof of concept available. Patch available. Sources: github.
github Patch Available🟡 PoC Available

JSON::ResumableParser#partial_value dereferences a freed input buffer and crashes on truncated duplicate-key streams · Advisory · ruby/json · GitHub

https://github.com/ruby/json/security/advisories/GHSA-9hj4-r449-hfvc

Vendor Advisories for CVE-2026-71847(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 rangeFixed inDependents
ruby-json2.15.2+dfsg-1 ... 2.9.1+dfsg-1 (15 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
ruby-json2.15.2+dfsg-1 ... 2.9.1+dfsg-1 (11 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
ruby-json2.15.2+dfsg-1 ... 2.9.1+dfsg-1 (8 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
ruby-json2.15.2+dfsg-1 ... 2.9.1+dfsg-1 (8 versions)——
RubyGems(1)
PackageVulnerable rangeFixed inDependents
json2.20.0, 2.21.0, 2.21.12.21.2—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 16× in last 7d / 32× 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.

  1. 2026-08-21 03:27 UTCEG score recompute
  2. 2026-08-20 22:56 UTCEPSS rescore
  3. 2026-08-20 00:04 UTCEG score recompute
  4. 2026-08-19 17:04 UTCEPSS rescore
  5. 2026-08-18 21:45 UTCEG score recompute
  6. 2026-08-18 13:49 UTCEPSS rescore
  7. 2026-08-18 13:49 UTCEPSS rescore
  8. 2026-08-17 19:24 UTCEG score recompute
  9. 2026-08-17 13:47 UTCEPSS rescore
  10. 2026-08-16 17:00 UTCEG score recompute
  11. 2026-08-16 14:56 UTCEPSS rescore
  12. 2026-08-16 14:56 UTCEPSS rescore
  13. 2026-08-16 03:51 UTCEG score recompute
  14. 2026-08-16 02:15 UTCEPSS rescore
  15. 2026-08-15 01:32 UTCEG score recompute
  16. 2026-08-15 01:31 UTCEPSS rescore
  17. 2026-08-13 23:13 UTCEG score recompute
  18. 2026-08-13 22:00 UTCEPSS rescore
  19. 2026-08-12 20:54 UTCEG score recompute
  20. 2026-08-12 13:51 UTCEPSS rescore
  21. 2026-08-11 18:36 UTCEG score recompute
  22. 2026-08-11 05:27 UTCEG score recompute
  23. 2026-08-11 00:00 UTCEPSS rescore
  24. 2026-08-09 14:00 UTCEG score recompute
  25. 2026-08-09 13:47 UTCEPSS rescore
Show 7 more
  1. 2026-08-09 00:51 UTCEG score recompute
  2. 2026-08-08 16:37 UTCEPSS rescore
  3. 2026-08-07 22:33 UTCEG score recompute
  4. 2026-08-07 21:22 UTCEG score recompute
  5. 2026-08-07 19:28 UTCEG score recompute
  6. 2026-08-07 18:47 UTCEG score recompute
  7. 2026-08-07 18:47 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-71847?
CVE-2026-71847 is a high vulnerability published on August 7, 2026. Ruby JSON is a JSON implementation for Ruby. From 2.20.0 until 2.21.2, Ruby's JSON native C extension clears the consumed JSON::ResumableParser input buffer but leaves state.start, state.cursor, and state.end pointing into released storage. When partialvalue reconstructs an incomplete object…
When was CVE-2026-71847 disclosed?
CVE-2026-71847 was first published in the National Vulnerability Database on August 7, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-71847 actively exploited?
CVE-2026-71847 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 83.0% of all scored CVEs.
What is the CVSS score of CVE-2026-71847?
CVE-2026-71847 has a CVSS v3 base score of 8.7 (NVD).
How do I remediate CVE-2026-71847?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-71847, 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

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