CVE-2026-8657
jsondiffpatch patch APIs are vulnerable to prototype pollution
Versions of the package jsondiffpatch before 0.7.6 are vulnerable to Prototype Pollution via the jsondiffpatch.patch() and jsondiffpatch/formatters/jsonpatch.patch() APIs. An attacker can perform prototype pollution by supplying crafted delta or JSON Patch documents, as attacker-controlled property names and path segments are used to traverse and modify objects without restricting access to special properties like proto or constructor.prototype, allowing modification of Object.prototype.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
8.8
Versions of the package jsondiffpatch before 0.7.6 are vulnerable to Prototype Pollution via the jsondiffpatch.patch() and jsondiffpatch/formatters/jsonpatch.patch() APIs. An attacker can perform prototype pollution by supplying crafted delta or JSON Patch documents, as attacker-controlled property names and path segments are used to traverse and modify objects without restricting access to special properties like proto or constructor.prototype, allowing modification of Object.prototype.
- Record
CVE-2026-8657- CVSS 4.0
- 8.8 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N/E:P - CVSS 3.1
- 8.2 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L/E:P - Weakness
- CWE-1321, CWE-1321
- Updated
- 2026-11-02
EUVDEUVD-2026-30670
8.8
Versions of the package jsondiffpatch before 0.7.6 are vulnerable to Prototype Pollution via the jsondiffpatch.patch() and jsondiffpatch/formatters/jsonpatch.patch() APIs. An attacker can perform prototype pollution by supplying crafted delta or JSON Patch documents, as attacker-controlled property names and path segments are used to traverse and modify objects without restricting access to special properties like proto or constructor.prototype, allowing modification of Object.prototype.
- Record
EUVD-2026-30670- CVSS 4.0
- 8.8 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N/E:P - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-j4fx-xxwh-2485
7.8
jsondiffpatch patch APIs are vulnerable to prototype pollution
Versions of the package jsondiffpatch before 0.7.6 are vulnerable to Prototype Pollution via the jsondiffpatch.patch() and jsondiffpatch/formatters/jsonpatch.patch() APIs. An attacker can perform prototype pollution by supplying crafted delta or JSON Patch documents, as attacker-controlled property names and path segments are used to traverse and modify objects without restricting access to special properties like proto or constructor.prototype, allowing modification of Object.prototype.
- Record
GHSA-j4fx-xxwh-2485- CVSS 4.0
- 7.8 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N/E:P - CVSS 3.1
- 8.2 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L - Weakness
- CWE-1321
- Updated
- 2026-11-02
NVD
7.8
Versions of the package jsondiffpatch before 0.7.6 are vulnerable to Prototype Pollution via the jsondiffpatch.patch() and jsondiffpatch/formatters/jsonpatch.patch() APIs. An attacker can perform prototype pollution by supplying crafted delta or JSON Patch documents, as attacker-controlled property names and path segments are used to traverse and modify objects without restricting access to special properties like proto or constructor.prototype, allowing modification of Object.prototype.
- Record
CVE-2026-8657- CVSS 4.0
- 7.8 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/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 - CVSS 3.1
- 8.2 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L - Weakness
- CWE-1321
- Updated
- 2026-11-02
OSV
7.8
Versions of the package jsondiffpatch before 0.7.6 are vulnerable to Prototype Pollution via the jsondiffpatch.patch() and jsondiffpatch/formatters/jsonpatch.patch() APIs. An attacker can perform prototype pollution by supplying crafted delta or JSON Patch documents, as attacker-controlled property names and path segments are used to traverse and modify objects without restricting access to special properties like proto or constructor.prototype, allowing modification of Object.prototype.
- Record
CVE-2026-8657- CVSS 4.0
- 7.8 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N/E:P - Weakness
- CWE-1321
- Updated
- 2026-11-02
OSVGHSA-j4fx-xxwh-2485
7.8
jsondiffpatch patch APIs are vulnerable to prototype pollution
Versions of the package jsondiffpatch before 0.7.6 are vulnerable to Prototype Pollution via the jsondiffpatch.patch() and jsondiffpatch/formatters/jsonpatch.patch() APIs. An attacker can perform prototype pollution by supplying crafted delta or JSON Patch documents, as attacker-controlled property names and path segments are used to traverse and modify objects without restricting access to special properties like proto or constructor.prototype, allowing modification of Object.prototype.
- Record
GHSA-j4fx-xxwh-2485- CVSS 4.0
- 7.8 High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N/E:P - CVSS 3.1
- 8.2 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L - Weakness
- CWE-1321
- Updated
- 2026-11-02
OSVROOT-APP-NPM-CVE-2026-8657 No score
CVE-2026-8657 in jsondiffpatch - Patched by Root
Root has patched CVE-2026-8657 in the jsondiffpatch package for Root:npm. Multiple fixed versions available.
- Record
ROOT-APP-NPM-CVE-2026-8657- Updated
- 2026-11-02
Affected packages
| Package | Affected | Fixed |
|---|---|---|
jsondiffpatchnpm |
before 0.7.6 | 0.7.6 |
jsondiffpatchRoot:npm |
before 0.6.0-aikido.3 | 0.6.0-aikido.3 |
@rootio/jsondiffpatchRoot:npm |
before 0.6.0-root.io.3 | 0.6.0-root.io.3 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-8657 is a high vulnerability (CVSS 8.8) in jsondiffpatch, published May 16, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.38%, the 31st percentile. Fixed in jsondiffpatch 0.7.6.
References
security.snyk.io/vuln/SNYK-JS-JSONDIFFPATCH-16322990
security.snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-16732792
gist.github.com/yuki-matsuhashi/e570fb1579ae1f3190059b622b0473fb
github.com/benjamine/jsondiffpatch/blob/96112c35a98f9201dd75d67fcee68a952c79e2fe/packages/jsondiffpatch/src/filters/nested.ts%23L82-L87
github.com/benjamine/jsondiffpatch/blob/96112c35a98f9201dd75d67fcee68a952c79e2fe/packages/jsondiffpatch/src/filters/nested.ts%23L107-L115
github.com/benjamine/jsondiffpatch/blob/96112c35a98f9201dd75d67fcee68a952c79e2fe/packages/jsondiffpatch/src/formatters/jsonpatch-apply.ts%23L146-L168
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github.com/benjamine/jsondiffpatch/blob/96112c35a98f9201dd75d67fcee68a952c79e2fe/packages/jsondiffpatch/src/formatters/jsonpatch-apply.ts%23L171-L199
github.com/benjamine/jsondiffpatch/commit/381c0125efab49f6f0dbc08317d01d55717672af
nvd.nist.gov/vuln/detail/CVE-2026-8657
github.com/advisories/GHSA-j4fx-xxwh-2485
github.com/CVEProject/cvelistV5/tree/main/cves/2026/8xxx/CVE-2026-8657.json
github.com/benjamine/jsondiffpatch