protobufjs compiles protobuf definitions into JavaScript (JS) functions. Prior to 7.6.5 and 8.6.6, protobufjs parsed option names by advancing through schema tokens until reaching an = token without checking for end of input, so a crafted .proto schema that opens an option declaration and ends prematurely can cause parse, Root.load, or Root.loadSync to loop indefinitely. This issue is fixed in versions 7.6.5 and 8.6.6.
CVE-2026-59877
HIGHNVD 7.57.5—Trending — 4 sources updated this week
EchelonGraph scoreMEDIUM confidence
This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 71% 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, nvd
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.5Exploit: NoneExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 7.5
- EG Score
- 7.5(medium)
- EPSS
- 29.1%
- KEV
- Not listed
Published
July 8, 2026
Last Modified
July 10, 2026
Advisory Details (6)
Auto-updated Jul 8, 2026Patch available. Sources: github_commit, github_pr, github_release, github.
github Patch Available
Denial of Service via infinite loop in .proto option parsing · Advisory · protobufjs/protobuf.js · GitHub
https://github.com/protobufjs/protobuf.js/security/advisories/GHSA-j3f2-48v5-ccwwgithub_release Patch Available
protobufjs: v8.6.6
Patch available: protobufjs/protobuf.js protobufjs-v8.6.6
https://github.com/protobufjs/protobuf.js/releases/tag/protobufjs-v8.6.6github_release Patch Available
protobufjs: v7.6.5
Patch available: protobufjs/protobuf.js protobufjs-v7.6.5
https://github.com/protobufjs/protobuf.js/releases/tag/protobufjs-v7.6.5github_pr Patch Available
fix: handle EOF during options parsing
Patch available: protobufjs/protobuf.js protobufjs-cli-v2.5.7 (PR #2352 merged 2026-07-03)
https://github.com/protobufjs/protobuf.js/pull/2352github_commit Patch Available
commit fa5c73add738 (protobufjs/protobuf.js)
Patch available: protobufjs/protobuf.js protobufjs-cli-v2.5.7 (contains commit fa5c73add738)
https://github.com/protobufjs/protobuf.js/commit/fa5c73add738ceb471e74da8cc2f3727c3d0a69fgithub_commit Patch Available
commit 10fba6d54815 (protobufjs/protobuf.js)
Patch available: protobufjs/protobuf.js protobufjs-v7.6.5 (contains commit 10fba6d54815)
https://github.com/protobufjs/protobuf.js/commit/10fba6d54815ceecca8a06b9a6db490c8f5d2217Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 13× in last 7d / 13× 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.
- 2026-07-12 11:26 UTCEG score recompute
- 2026-07-12 05:46 UTCEPSS rescore
- 2026-07-12 00:23 UTCEG score recompute
- 2026-07-11 13:21 UTCEG score recompute▲ 2.20
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-10 20:19 UTCNVD updateCVSS v3 → 7.5 · severity → HIGH
- 2026-07-10 14:10 UTCEG score recompute
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-09 14:57 UTCEG score recompute
- 2026-07-08 15:46 UTCEG score recompute
- 2026-07-08 15:45 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-59877?
CVE-2026-59877 is a high vulnerability published on July 8, 2026. protobufjs compiles protobuf definitions into JavaScript (JS) functions. Prior to 7.6.5 and 8.6.6, protobufjs parsed option names by advancing through schema tokens until reaching an = token without checking for end of input, so a crafted .proto schema that opens an option declaration and ends…
When was CVE-2026-59877 disclosed?
CVE-2026-59877 was first published in the National Vulnerability Database on July 8, 2026, with the most recent update on July 10, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-59877 actively exploited?
CVE-2026-59877 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 29.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-59877?
CVE-2026-59877 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-59877?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-59877, 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
Explore the affected products and dependency analysis for CVE-2026-59877
Is Your Infrastructure Affected by CVE-2026-59877?
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