GraphQL Tools provides utilities for building, stitching, and mocking GraphQL schemas. Prior to 12.0.1, the GraphQL Tools utils package's mergeDeep function follows inherited properties while recursively merging source objects and does not exclude __proto__, constructor, or prototype keys. An unauthenticated GraphQL client can alias fields to those names so responses from two subgraphs collide during ordinary supergraph result merging, causing mergeDeep to traverse Object and Function prototypes and overwrite Function.prototype.call with a subgraph-supplied value. This breaks subsequent requests in the process until restart. This issue is fixed in version 12.0.1.
CVE-2026-104852
HIGHPre-NVD 8.28.2
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: None knownExposed services: Not assessed
The CVE record names the fixed release — apply it.
- CVSS v3
- 8.2
- EG Score
- 8.2HIGHlow confidence
- EG Risk
- 41EG Risk 41/100CISA SSVC
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%Exploitation0% × 40%Automatability30% × 15%CISA SSVC: Track at low or medium mission impact; Track or Attend at high (mission-essential systems).Action: The CVE record names the fixed release. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high. - EPSS PROB
- —
- EPSS %ILE
- —
- KEV
- Not listed
CISA SSVCTrack at low or medium mission impact; Track or Attend at high (mission-essential systems).
The CVE record names the fixed release. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table
Published
October 5, 2026
Last Modified
October 5, 2026
Advisory Details (4)
Auto-updated Oct 5, 2026Fix named in the CVE record. Sources: github, github_pr, github_commit.
github_commit
commit 0b9529f1988f (ardatan/graphql-tools)
Fix landed in ardatan/graphql-tools commit 0b9529f1988f — awaiting tagged release
https://github.com/ardatan/graphql-tools/commit/0b9529f1988fd36186a7c106a6efe0356f1b7f2egithub_pr
Drop prototype polluting keys from subgraph results before merging them
Fix merged in graphql-hive/gateway PR #2600 on 2026-09-07 — awaiting tagged release
https://github.com/graphql-hive/gateway/pull/2600github_pr
Fix prototype pollution in `mergeDeep`
Fix merged in ardatan/graphql-tools PR #8423 on 2026-09-07 — awaiting tagged release
https://github.com/ardatan/graphql-tools/pull/8423githubMentions a patch (unverified)
Prototype pollution in well-established utility function `mergeDeep` · Advisory · ardatan/graphql-tools · GitHub
https://github.com/ardatan/graphql-tools/security/advisories/GHSA-7mx3-vvmw-hjmvVendor Advisories for CVE-2026-104852(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 3× in last 7d / 3× 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.
- 2026-10-05 23:26 UTCEG score recompute
- 2026-10-05 23:01 UTCEG score recompute
- 2026-10-05 23:00 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(4)
What is CVE-2026-104852?
CVE-2026-104852 is a high vulnerability published on October 5, 2026. GraphQL Tools provides utilities for building, stitching, and mocking GraphQL schemas. Prior to 12.0.1, the GraphQL Tools utils package's mergeDeep function follows inherited properties while recursively merging source objects and does not exclude proto, constructor, or prototype keys. An…
When was CVE-2026-104852 disclosed?
CVE-2026-104852 was first published on October 5, 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-2026-104852?
CVE-2026-104852 has a CVSS base score of 8.2 (a secondary CVSS source that NVD displays; NVD's own analysis pending). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-104852?
The CVE record for CVE-2026-104852 names the fix: "This issue is fixed in version 12.0.1." The vendor advisories EchelonGraph has for CVE-2026-104852 are linked in the Vendor Advisories panel on this page.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-104852
Is Your Infrastructure Affected by CVE-2026-104852?
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