protobufjs : Schema-derived names can shadow runtime-significant properties

Exploitation

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

CVSS

5.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS

• CVE-2026-54269: 0.40% estimated exploitation activity in the next 30 days; percentile 34.52 (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.

Summary protobufjs accepted certain schema-derived names that could collide with properties used by protobufjs runtime helpers. The known affected names are fields named hasOwnProperty, field or oneof names such as $type when loaded through protobufjs JSON/reflection descriptors, and service methods whose generated helper name is rpcCall. When affected message or service types were used, protobufjs could read schema-controlled data where it expected an own-property helper, reflected type metadata, or the base RPC helper. This could cause deterministic exceptions or recursive calls in affected decode post-checks, verification, object conversion, reflected JSON serialization, or protobufjs RPC helper invocation. Impact An attacker who can provide or influence protobuf schemas or protobufjs JSON descriptors may be able to make affected message or service types unusable, resulting in denial of service for the affected processing path. Applications using only trusted schemas are affected…

Published by the source

15 Jun 2026, 17:27 UTC

Last modified by the source

10 Sep 2026, 03:50 UTC

Source last checked

26 Oct 2026, 12:57 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-f38q-mgvj-vph7

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-f38q-mgvj-vph7

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# Patch Next advisory brief: CVE-2026-54269

Advisory: protobufjs : Schema-derived names can shadow runtime-significant properties
IDs: CVE-2026-54269, GHSA-f38q-mgvj-vph7
Record: https://patchnext.com/advisories/cve-2026-54269 (revision 2, source checked 26 Oct 2026, 12:57 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: protobufjs 8.6.0, 7.6.3; protobufjs-cli 2.5.1, 1.3.3. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm protobufjs: affected <= 7.6.2; >= 8.0.0, <= 8.5.0; fixed in 7.6.3, 8.6.0
- npm protobufjs-cli: affected >= 2.0.0, <= 2.5.0; <= 1.3.2; fixed in 2.5.1, 1.3.3

## Suggested inspection (read-only)
- `npm ls protobufjs --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- `npm ls protobufjs-cli --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 protobufjs, protobufjs-cli.
- 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-f38q-mgvj-vph7 (OSV record GHSA-f38q-mgvj-vph7 lists affected ranges: npm protobufjs >=0 =8.0.0 =2.0.0 =0 <1.3.3 (fixed))
- Verified: https://github.com/advisories/GHSA-f38q-mgvj-vph7 (GitHub-reviewed advisory GHSA-f38q-mgvj-vph7 lists affected ranges: npm protobufjs >=0 =8.0.0 =2.0.0 =0 <=1.3.2)

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