Vue I18n Allows Prototype Pollution in handleFlatJson

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

8.9 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P · score source

EPSS

• CVE-2025-27597: 0.63% estimated exploitation activity in the next 30 days; percentile 50.01 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Vulnerability type: Prototype Pollution Vulnerability Location(s): Description: The latest version of @intlify/message-resolver (9.1) and @intlify/vue-i18n-core (9.2 or later), (previous versions might also affected), is vulnerable to Prototype Pollution through the entry function(s) handleFlatJson. An attacker can supply a payload with Object.prototype setter to introduce or modify properties within the global prototype chain, causing denial of service (DoS) a the minimum consequence. Moreover, the consequences of this vulnerability can escalate to other injection-based attacks, depending on how the library integrates within the application. For instance, if the polluted property propagates to sensitive Node.js APIs (e.g., exec, eval), it could enable an attacker to execute arbitrary commands within the application's context. PoC:

Published by the source

7 Mar 2025, 15:58 UTC

Last modified by the source

26 Aug 2026, 01:21 UTC

Source last checked

26 Oct 2026, 13:01 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-p2ph-7g93-hw3m

2. Revision 2 · amended · 25 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-p2ph-7g93-hw3m

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# Patch Next advisory brief: CVE-2025-27597

Advisory: Vue I18n Allows Prototype Pollution in `handleFlatJson`
IDs: CVE-2025-27597, GHSA-p2ph-7g93-hw3m
Record: https://patchnext.com/advisories/cve-2025-27597 (revision 3, source checked 26 Oct 2026, 13:01 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @intlify/message-resolver 9.1.11; @intlify/vue-i18n-core 11.1.2, 10.0.6, 9.14.3; vue-i18n 11.1.2, 10.0.6, 9.14.3; petite-vue-i18n 11.1.2, 10.0.6; @intlify/core-base 9.1.11; @intlify/core 9.1.11. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @intlify/message-resolver: affected >= 9.1.0, < 9.1.11; fixed in 9.1.11
- npm @intlify/vue-i18n-core: affected >= 9.2.0, < 9.14.3; >= 10.0.0-alpha.1, < 10.0.6; >= 11.0.0-beta.0, < 11.1.2; fixed in 11.1.2, 9.14.3, 10.0.6
- npm vue-i18n: affected >= 9.1.0, < 9.14.3; >= 10.0.0-alpha.1, < 10.0.6; >= 11.0.0-beta.0, < 11.1.2; fixed in 11.1.2, 9.14.3, 10.0.6
- npm petite-vue-i18n: affected >= 10.0.0, < 10.0.6; >= 11.0.0-beta.0, < 11.1.2; fixed in 11.1.2, 10.0.6
- npm @intlify/core-base: affected >= 9.1.0, < 9.1.11; fixed in 9.1.11
- npm @intlify/core: affected >= 9.1.0, < 9.1.11; fixed in 9.1.11

## Suggested inspection (read-only)
- `npm ls @intlify/message-resolver --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- `npm ls @intlify/vue-i18n-core --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- `npm ls vue-i18n --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- `npm ls petite-vue-i18n --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- `npm ls @intlify/core-base --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- `npm ls @intlify/core --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @intlify/message-resolver, @intlify/vue-i18n-core, vue-i18n, petite-vue-i18n, @intlify/core-base, @intlify/core.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-p2ph-7g93-hw3m (OSV record GHSA-p2ph-7g93-hw3m lists affected ranges: npm @intlify/message-resolver >=9.1.0 =9.2.0 =10.0.0-alpha.1 =11.0.0-beta.0 =10.0.0 =11.0.0-beta.0 =9.1.0 =10.0.0-alpha.1 =11.0.0-beta.0 =9.1.0 =9.1.0 <9.1.11…)
- Verified: https://github.com/advisories/GHSA-p2ph-7g93-hw3m (GitHub-reviewed advisory GHSA-p2ph-7g93-hw3m lists affected ranges: npm @intlify/message-resolver >=9.1.0 =9.2.0 =10.0.0-alpha.1 =11.0.0-beta.0 =10.0.0 =11.0.0-beta.0 =9.1.0 =10.0.0-alpha.1 =11.0.0-beta.0 =9.1.0 =9.1.0 <9.1.11)

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