GHSA-94RC-8X27-4472
Vulnerability from github – Published: 2026-06-15 20:13 – Updated: 2026-07-15 22:06Summary
protobufjs 8.2.0 added support for preserving unknown fields encountered during binary decode. Affected versions preserved unknown wire elements in message.$unknowns and did not provide a decode-time option to discard unknown fields before retaining them.
A crafted protobuf payload containing many unknown fields could therefore cause a decoded message to retain substantially more memory than the input size would suggest, even when unknown-field round-tripping is not needed. protobufjs 8.5.0 added the relevant decode-time options, allowing applications that decode untrusted protobuf data to disable unknown-field retention during decode. protobufjs 8.6.2 flips the default so unknown fields are discarded unless explicitly opted into.
Impact
An attacker who can provide protobuf binary data decoded by an application using affected protobufjs versions may be able to increase memory pressure by sending messages with many unknown fields. This can degrade availability or contribute to process termination in services that decode and retain attacker-controlled messages.
This issue affects applications that decode untrusted protobuf binary input and do not need unknown-field round-tripping. Applications that only decode trusted protobuf data, already enforce input-size/concurrency limits, or do not retain decoded messages beyond immediate processing are less directly affected.
Preconditions
- The application must decode protobuf binary data influenced by an attacker.
- The decoded schema must not define the attacker-selected field numbers, causing those fields to be treated as unknown.
- The application must use a protobufjs version that preserves unknown fields but does not provide a decode-time discard option.
- The decoded message, or enough decoded messages concurrently, must remain live long enough for retained unknown-field data to affect memory usage.
Workarounds
Upgrade to protobufjs 8.5.0 or newer and disable unknown-field preservation if not needed: Create a Reader, set reader.discardUnknown = true, and decode from that reader, or make this the default for subsequently created readers by setting Reader.discardUnknown = true. When upgrading to protobufjs 8.6.2 or newer, unknown fields are discarded by default unless opted into by setting discardUnknown = false.
Applications should also continue to enforce input-size, request concurrency, and request timeout limits at their transport or application boundary.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 8.4.2"
},
"package": {
"ecosystem": "npm",
"name": "protobufjs"
},
"ranges": [
{
"events": [
{
"introduced": "8.2.0"
},
{
"fixed": "8.5.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-54270"
],
"database_specific": {
"cwe_ids": [
"CWE-770"
],
"github_reviewed": true,
"github_reviewed_at": "2026-06-15T20:13:28Z",
"nvd_published_at": "2026-06-22T18:16:45Z",
"severity": "MODERATE"
},
"details": "## Summary\n\nprotobufjs 8.2.0 added support for preserving unknown fields encountered during binary decode. Affected versions preserved unknown wire elements in `message.$unknowns` and did not provide a decode-time option to discard unknown fields before retaining them.\n\nA crafted protobuf payload containing many unknown fields could therefore cause a decoded message to retain substantially more memory than the input size would suggest, even when unknown-field round-tripping is not needed. protobufjs 8.5.0 added the relevant decode-time options, allowing applications that decode untrusted protobuf data to disable unknown-field retention during decode. protobufjs 8.6.2 flips the default so unknown fields are discarded unless explicitly opted into.\n\n## Impact\n\nAn attacker who can provide protobuf binary data decoded by an application using affected protobufjs versions may be able to increase memory pressure by sending messages with many unknown fields. This can degrade availability or contribute to process termination in services that decode and retain attacker-controlled messages.\n\nThis issue affects applications that decode untrusted protobuf binary input and do not need unknown-field round-tripping. Applications that only decode trusted protobuf data, already enforce input-size/concurrency limits, or do not retain decoded messages beyond immediate processing are less directly affected.\n\n## Preconditions\n\n* The application must decode protobuf binary data influenced by an attacker.\n* The decoded schema must not define the attacker-selected field numbers, causing those fields to be treated as unknown.\n* The application must use a protobufjs version that preserves unknown fields but does not provide a decode-time discard option.\n* The decoded message, or enough decoded messages concurrently, must remain live long enough for retained unknown-field data to affect memory usage.\n\n## Workarounds\n\nUpgrade to protobufjs 8.5.0 or newer and disable unknown-field preservation if not needed: Create a `Reader`, set `reader.discardUnknown = true`, and decode from that reader, or make this the default for subsequently created readers by setting `Reader.discardUnknown = true`. When upgrading to protobufjs 8.6.2 or newer, unknown fields are discarded by default unless opted into by setting `discardUnknown = false`.\n\nApplications should also continue to enforce input-size, request concurrency, and request timeout limits at their transport or application boundary.",
"id": "GHSA-94rc-8x27-4472",
"modified": "2026-07-15T22:06:10Z",
"published": "2026-06-15T20:13:28Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/protobufjs/protobuf.js/security/advisories/GHSA-94rc-8x27-4472"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-54270"
},
{
"type": "PACKAGE",
"url": "https://github.com/protobufjs/protobuf.js"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
"type": "CVSS_V3"
}
],
"summary": "protobufjs: Memory amplification from preserved unknown fields in binary decode"
}
Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
How durations are calculated
Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.
Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.
Loading timeline…
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.