CVE-2026-54270

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 79% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
5.3
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.3Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

protobufjs compiles protobuf definitions into JavaScript (JS) functions. From 8.2.0 to 8.4.2, protobufjs 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.

CVSS v3
5.3
EG Score
5.3(medium)
EPSS
21.1%
KEV
Not listed

Published

June 15, 2026

Last Modified

June 24, 2026

Advisory Details (1)

Auto-updated Jun 23, 2026
Patch available. Sources: github.
github Patch Available

Memory amplification from preserved unknown fields in binary decode · Advisory · protobufjs/protobuf.js · GitHub

https://github.com/protobufjs/protobuf.js/security/advisories/GHSA-94rc-8x27-4472

Vendor Advisories for CVE-2026-54270(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFixed inDependents
protobufjs—8.5.0—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 16× in last 7d / 40× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-07 00:17 UTCEG score recompute
  2. 2026-07-06 16:27 UTCEPSS rescore
  3. 2026-07-06 16:27 UTCEPSS rescore
  4. 2026-07-06 02:23 UTCEPSS rescore
  5. 2026-07-06 02:23 UTCEPSS rescore
  6. 2026-07-05 11:44 UTCEG score recompute
  7. 2026-07-05 02:31 UTCEPSS rescore
  8. 2026-07-05 02:30 UTCEPSS rescore
  9. 2026-07-04 09:59 UTCEG score recompute
  10. 2026-07-04 06:31 UTCEPSS rescore
  11. 2026-07-04 06:31 UTCEPSS rescore
  12. 2026-07-03 00:21 UTCEG score recompute
  13. 2026-07-01 22:43 UTCEG score recompute
  14. 2026-07-01 15:07 UTCEPSS rescore
  15. 2026-06-30 23:22 UTCEPSS rescore
  16. 2026-06-30 20:31 UTCEG score recompute
  17. 2026-06-29 18:53 UTCEG score recompute
  18. 2026-06-29 14:06 UTCEPSS rescore
  19. 2026-06-29 14:06 UTCEPSS rescore
  20. 2026-06-28 17:16 UTCEG score recompute
  21. 2026-06-28 14:07 UTCEPSS rescore
  22. 2026-06-28 04:56 UTCEPSS rescore
  23. 2026-06-28 04:56 UTCEPSS rescore
  24. 2026-06-27 15:37 UTCEG score recompute
  25. 2026-06-27 03:08 UTCEPSS rescore
Show 15 more
  1. 2026-06-26 13:59 UTCEG score recompute
  2. 2026-06-25 13:49 UTCEPSS rescore
  3. 2026-06-25 12:14 UTCEG score recompute
  4. 2026-06-24 14:05 UTCEPSS rescore
  5. 2026-06-24 10:37 UTCEG score recompute
  6. 2026-06-23 21:33 UTCEPSS rescore
  7. 2026-06-23 21:33 UTCEPSS rescore
  8. 2026-06-23 08:50 UTCEG score recompute
  9. 2026-06-22 07:10 UTCEG score recompute
  10. 2026-06-21 05:18 UTCEG score recompute
  11. 2026-06-20 03:32 UTCEG score recompute
  12. 2026-06-19 01:40 UTCEG score recompute
  13. 2026-06-18 00:02 UTCEG score recompute
  14. 2026-06-16 22:24 UTCEG score recompute
  15. 2026-06-15 20:47 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-54270?
CVE-2026-54270 is a medium vulnerability published on June 15, 2026. protobufjs compiles protobuf definitions into JavaScript (JS) functions. From 8.2.0 to 8.4.2, protobufjs 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…
When was CVE-2026-54270 disclosed?
CVE-2026-54270 was first published in the National Vulnerability Database on June 15, 2026, with the most recent update on June 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-54270 actively exploited?
CVE-2026-54270 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 21.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-54270?
CVE-2026-54270 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2026-54270?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-54270, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-54270

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