EUVD-2026-37991
GHSA-87mf-gv2c-c62c
Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Network-reachable with no authentication required (PR:N); impact is limited to a process crash with no data exposure or integrity change, so C:N/I:N/A:L.
Primary rating from Vendor (snyk).
CVSS VectorVendor: snyk
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Lifecycle Timeline
4Blast Radius
ecosystem impact- 100 npm packages depend on ts-deepmerge (25 direct, 77 indirect)
Ecosystem-wide dependent count for version 8.0.0.
DescriptionCVE.org
Versions of the package ts-deepmerge before 8.0.0 are vulnerable to Uncaught Exception due to the improper handling of built-in Object.prototype methods (such as toString, valueOf). When user-controlled input contains these keys with non-function values, the resulting merged object becomes broken - any string context operation throws a TypeError, crashing the application.
AnalysisAI
Uncaught Exception in ts-deepmerge before 8.0.0 allows unauthenticated remote attackers to crash Node.js applications by supplying JSON payloads that contain Object.prototype method names (e.g., toString, valueOf) mapped to non-function values, causing any subsequent string-context operation on the merged object to throw a TypeError. The vulnerability is distinct from classic prototype pollution - it does not escalate privileges or leak data, but reliably corrupts the merged object's callable methods, making DoS trivially achievable against any network-exposed merge endpoint that accepts untrusted input. …
Unlock full vulnerability intelligence
- Risk assessment & exploitation conditions
- Attack chain visualization
- Remediation with exact patch versions
- Threat intelligence from 22 sources
- Personal watchlist & email alerts
Free forever · No credit card required
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires two conditions to be simultaneously true: first, the application must pass user-controlled input - without stripping Object.prototype method names - into ts-deepmerge's merge() function; second, a code path must subsequently perform a string-context operation on the merged output object (template literal, string concatenation, console.log, or similar). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 base vector (AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N) yields a score of 5.5, reflecting a network-reachable, low-complexity, unauthenticated attack with limited availability impact confined to the vulnerable system and no confidentiality or integrity impact - fully consistent with a targeted DoS primitive rather than a code execution path. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker identifies an API endpoint - such as a settings update, profile merge, or configuration patch route - that accepts arbitrary JSON and internally passes user input to ts-deepmerge's merge() function without key sanitization. The attacker submits a minimal payload such as {"toString": 1} in the request body. … |
| Remediation | Upgrade ts-deepmerge to version 8.0.0 or later, which introduces the UNSAFE_KEYS blocklist covering __proto__, constructor, prototype, toString, valueOf, hasOwnProperty, isPrototypeOf, propertyIsEnumerable, and toLocaleString. … Detailed patch versions, workarounds, and compensating controls in full report. |
Threat intelligence, references, and detailed analysis are available after sign-in.
Same weakness CWE-248 – Uncaught Exception
View allSame technique Denial Of Service
View allShare
External POC / Exploit Code
Leaving vuln.today