CVE-2026-40345

HIGHPre-NVD 8.28.2—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 8.2 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
Elevated
8.2EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 8.2Exploit: Elevated riskExposed: 0

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

deepmerge-ts is a typescript library providing functionality to deep merging of javascript objects. Prior to 8.0.0, the deepmerge, deepmergeCustom, deepmergeInto, and deepmergeIntoCustom APIs do not track visited objects or object pairs when recursively merging records. When two input values contain self-references at the same property path, the merge logic repeatedly revisits the same pair until Node.js raises RangeError: Maximum call stack size exceeded. Applications that merge attacker-controlled recursive object graphs can synchronously crash the affected process or cause repeated worker restarts. Plain JSON input alone cannot create the recursive graph required to trigger the issue. This issue is fixed in version 8.0.0.

CVSS v3
8.2
EG Score
8.2(medium)
EG Risk
53(Track)
EG Risk 53/100SSVC: 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
Severity82% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
40%
KEV
Not listed

Published

August 17, 2026

Last Modified

September 18, 2026

Advisory Details (4)

Auto-updated Aug 20, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_pr, github_commit, github_release.
github_release Patch Available

v8.0.0

Patch available: RebeccaStevens/deepmerge-ts v8.0.0

https://github.com/RebeccaStevens/deepmerge-ts/releases/tag/v8.0.0
github_commit Patch Available

commit 398492757b3f (RebeccaStevens/deepmerge-ts)

Patch available: RebeccaStevens/deepmerge-ts v8.0.0 (contains commit 398492757b3f)

https://github.com/RebeccaStevens/deepmerge-ts/commit/398492757b3f22a0d7d89b09ce1ae9cd32806c9a
github_pr

feat: add circular reference support, maxDepth option, and hierarchy tracking

Fix merged in RebeccaStevens/deepmerge-ts PR #707 on 2026-08-12 — awaiting tagged release

https://github.com/RebeccaStevens/deepmerge-ts/pull/707
github Patch Available🟡 PoC Available

Stack exhaustion when merging recursive object graphs · Advisory · RebeccaStevens/deepmerge-ts · GitHub

https://github.com/RebeccaStevens/deepmerge-ts/security/advisories/GHSA-ggr8-5vv4-36mx

Vendor Advisories for CVE-2026-40345(1)

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

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFixed inDependents
deepmerge-ts—8.0.0—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 15× in last 7d / 59× 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. 2026-09-18 20:24 UTCEG score recompute
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-18 19:28 UTCEPSS rescore
  4. 2026-09-18 00:18 UTCEG score recompute
  5. 2026-09-17 19:30 UTCEPSS rescore
  6. 2026-09-17 00:28 UTCEG score recompute
  7. 2026-09-16 14:08 UTCEPSS rescore
  8. 2026-09-16 12:41 UTCEG score recompute
  9. 2026-09-16 05:15 UTCEPSS rescore
  10. 2026-09-15 12:57 UTCEG score recompute
  11. 2026-09-15 03:11 UTCEPSS rescore
  12. 2026-09-14 01:35 UTCEG score recompute
  13. 2026-09-13 16:47 UTCEPSS rescore
  14. 2026-09-13 02:03 UTCEG score recompute
  15. 2026-09-12 15:01 UTCEPSS rescore
  16. 2026-09-12 02:30 UTCEG score recompute
  17. 2026-09-11 14:53 UTCEPSS rescore
  18. 2026-09-11 14:44 UTCEG score recompute
  19. 2026-09-11 09:37 UTCEPSS rescore
  20. 2026-09-10 15:11 UTCEG score recompute
  21. 2026-09-10 09:34 UTCEPSS rescore
  22. 2026-09-09 03:41 UTCEG score recompute
  23. 2026-09-08 22:00 UTCEPSS rescore
  24. 2026-09-07 22:27 UTCEG score recompute
  25. 2026-09-07 16:01 UTCEPSS rescore
Show 35 more
  1. 2026-09-06 21:30 UTCEG score recompute
  2. 2026-09-06 13:47 UTCEPSS rescore
  3. 2026-09-05 21:56 UTCEG score recompute
  4. 2026-09-04 22:21 UTCEG score recompute
  5. 2026-09-04 10:24 UTCEG score recompute
  6. 2026-09-04 05:06 UTCEPSS rescore
  7. 2026-09-02 22:10 UTCEG score recompute
  8. 2026-09-02 14:12 UTCEPSS rescore
  9. 2026-09-01 21:37 UTCEG score recompute
  10. 2026-09-01 13:53 UTCEPSS rescore
  11. 2026-09-01 09:49 UTCEG score recompute
  12. 2026-09-01 04:39 UTCEPSS rescore
  13. 2026-08-31 06:49 UTCEG score recompute
  14. 2026-08-30 19:17 UTCEPSS rescore
  15. 2026-08-30 07:16 UTCEG score recompute
  16. 2026-08-30 01:22 UTCEPSS rescore
  17. 2026-08-29 05:39 UTCEG score recompute
  18. 2026-08-28 21:41 UTCEPSS rescore
  19. 2026-08-27 14:41 UTCEG score recompute
  20. 2026-08-27 14:25 UTCEPSS rescore
  21. 2026-08-26 15:08 UTCEG score recompute
  22. 2026-08-26 14:46 UTCEPSS rescore
  23. 2026-08-25 15:34 UTCEG score recompute
  24. 2026-08-25 13:49 UTCEPSS rescore
  25. 2026-08-24 16:02 UTCEG score recompute
  26. 2026-08-23 04:41 UTCEG score recompute
  27. 2026-08-23 00:19 UTCEPSS rescore
  28. 2026-08-22 05:08 UTCEG score recompute
  29. 2026-08-21 23:49 UTCEPSS rescore
  30. 2026-08-21 17:22 UTCEG score recompute
  31. 2026-08-21 16:51 UTCEG score recompute
  32. 2026-08-20 17:35 UTCEG score recompute
  33. 2026-08-20 16:52 UTCEG score recompute▲ 8.20
  34. 2026-08-20 16:51 UTCMITRE cvelistV5CVSS v3 → 8.2 · CVSS v4 → 8.2
  35. 2026-08-17 13:37 UTCEG score recompute

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCJvr2022/CVE-2026-40345
    First seen Aug 17, 2026

    A poc and write-up for CVE-2026-40345

    Open source ↗

Frequently asked(5)

What is CVE-2026-40345?
CVE-2026-40345 is a high vulnerability published on August 17, 2026. deepmerge-ts is a typescript library providing functionality to deep merging of javascript objects. Prior to 8.0.0, the deepmerge, deepmergeCustom, deepmergeInto, and deepmergeIntoCustom APIs do not track visited objects or object pairs when recursively merging records. When two input values…
When was CVE-2026-40345 disclosed?
CVE-2026-40345 was first published in the National Vulnerability Database on August 17, 2026, with the most recent update on September 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-40345 actively exploited?
CVE-2026-40345 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 60.4% of all scored CVEs.
What is the CVSS score of CVE-2026-40345?
CVE-2026-40345 has a CVSS v3 base score of 8.2 (NVD).
How do I remediate CVE-2026-40345?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-40345, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-40345

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