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.
CVE-2026-40345
HIGHPre-NVD 8.28.2Elevated
EchelonGraph scoreLOW confidence
This high-severity CVE scores 8.2 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). 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: secondary
8.2EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: —CVSS: 8.2Exploit: Elevated riskExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 8.2
- EG Score
- 8.2(low)
- EG Risk
- 57(Track)EG Risk 57/100SSVC: 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 computedSeverity82% × 45%Exploitation40% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- —
- EPSS %ILE
- —
- KEV
- Not listed
Published
August 17, 2026
Last Modified
August 20, 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/v8.0.0github_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/398492757b3f22a0d7d89b09ce1ae9cd32806c9agithub_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/707github 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-ggr8-5vv4-36mxVendor 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.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 4× in last 7d / 4× 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.
- 2026-08-20 17:35 UTCEG score recompute
- 2026-08-20 16:52 UTCEG score recompute▲ 8.20
- 2026-08-20 16:51 UTCMITRE cvelistV5CVSS v3 → 8.2 · CVSS v4 → 8.2
- 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-2026-40345First seen Aug 17, 2026
A poc and write-up for CVE-2026-40345
Open source ↗
Related CVEs(same CWE)
Frequently asked(4)
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 August 20, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-40345?
CVE-2026-40345 has a CVSS v3 base score of 8.2 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
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
Explore the affected products and dependency analysis for CVE-2026-40345
Is Your Infrastructure Affected by CVE-2026-40345?
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