CVE-2026-76821

HIGHPre-NVD 7.17.1—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5%, top 60% 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
Trending — 3 sources updated this week
7.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.1Exploit: None knownExposed: 0

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

OpenCTI is an open source platform for managing cyber threat intelligence knowledge and observables. Prior to 7.260706.0, the JSON ingestion mapper's extractWithRegexp formula function compiled a user-supplied regular expression with the JavaScript RegExp engine in opencti-platform/opencti-graphql/src/parser/json-mapper.ts without validating its complexity. An authenticated user with JSON mapper creation permission could provide a catastrophically backtracking pattern and matching ingestion input, blocking the Node.js event loop and making the GraphQL API unavailable to all users. Scheduled ingestion could repeatedly execute the malicious mapper without additional attacker action, and recovery could require disabling the mapper and restarting the process. The issue affects availability and does not expose or modify data. This issue is fixed in version 7.260706.0.

CVSS v3
7.1
EG Score
7.1(medium)
EG Risk
32(Track)
EG Risk 32/100SSVC: 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 computed
Severity71% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
40%
KEV
Not listed

Published

September 15, 2026

Last Modified

September 16, 2026

Advisory Details (4)

Auto-updated Sep 15, 2026
Patch available. Sources: github, github_pr, github_commit, github_release.
github_release Patch Available

Version 7.260706.0

Patch available: OpenCTI-Platform/opencti 7.260706.0

https://github.com/OpenCTI-Platform/opencti/releases/tag/7.260706.0
github_commit

commit 3d726c09480f (OpenCTI-Platform/opencti)

Fix landed in OpenCTI-Platform/opencti commit 3d726c09480f — awaiting tagged release

https://github.com/OpenCTI-Platform/opencti/commit/3d726c09480f96980ce4c3e6119a8034dbdf2c96
github_pr

feat(json-mapper): improve extractWithRegexp (#16929)

Fix merged in OpenCTI-Platform/opencti PR #16935 on 2026-07-02 — awaiting tagged release

https://github.com/OpenCTI-Platform/opencti/pull/16935
github Patch Available

User-Controlled ReDoS in JSON Ingestion Mapper · Advisory · OpenCTI-Platform/opencti · GitHub

https://github.com/OpenCTI-Platform/opencti/security/advisories/GHSA-7g3x-wc2m-9h9x

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 10× 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. 2026-09-19 20:30 UTCEG score recompute
  2. 2026-09-18 20:07 UTCEG score recompute
  3. 2026-09-18 19:28 UTCEPSS rescore
  4. 2026-09-17 19:45 UTCEG score recompute
  5. 2026-09-16 19:23 UTCEG score recompute
  6. 2026-09-16 18:52 UTCEG score recompute
  7. 2026-09-16 14:08 UTCEPSS rescore
  8. 2026-09-15 20:39 UTCEG score recompute
  9. 2026-09-15 19:43 UTCEG score recompute
  10. 2026-09-15 19:42 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-76821?
CVE-2026-76821 is a high vulnerability published on September 15, 2026. OpenCTI is an open source platform for managing cyber threat intelligence knowledge and observables. Prior to 7.260706.0, the JSON ingestion mapper's extractWithRegexp formula function compiled a user-supplied regular expression with the JavaScript RegExp engine in…
When was CVE-2026-76821 disclosed?
CVE-2026-76821 was first published in the National Vulnerability Database on September 15, 2026, with the most recent update on September 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-76821 actively exploited?
CVE-2026-76821 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 60.5% of all scored CVEs.
What is the CVSS score of CVE-2026-76821?
CVE-2026-76821 has a CVSS v3 base score of 7.1 (NVD).
How do I remediate CVE-2026-76821?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-76821, 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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