mammoth (aka mammoth.js) before 1.12.2 is vulnerable to prototype pollution when reading the styles defined in a document. Converting a crafted .docx file allows an attacker to add arbitrary properties to Object.prototype. In 1.11.0 through 1.12.1, applications that convert further documents in the same process and return the converted HTML can also disclose the contents of local server files (to the party supplying the documents) by setting externalFileAccess to true.
CVE-2026-97151
HIGHPre-NVD 8.48.4
EchelonGraph scoreLOW confidence
This high-severity CVE scores 8.4 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). 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: secondary
8.4EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: —CVSS: 8.4Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 8.4
- EG Score
- 8.4(low)
- EG Risk
- 42(Track)EG Risk 42/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity84% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- —
- EPSS %ILE
- —
- KEV
- Not listed
Published
September 24, 2026
Last Modified
September 24, 2026
Advisory Details (3)
Auto-updated Sep 24, 2026Upstream fix merged — awaiting tagged release. Sources: github_commit.
github_commit
commit 2888fa158d67 (mwilliamson/mammoth.js)
Fix landed in mwilliamson/mammoth.js commit 2888fa158d67 — awaiting tagged release
https://github.com/mwilliamson/mammoth.js/commit/2888fa158d67c1419199f152326e12a05618b53egithub_commit
commit 31f0c370be4b (mwilliamson/mammoth.js)
Fix landed in mwilliamson/mammoth.js commit 31f0c370be4b — awaiting tagged release
https://github.com/mwilliamson/mammoth.js/commit/31f0c370be4b95ac4fa285fea3be970606735f16Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 3× in last 7d / 3× 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.
- 2026-09-24 04:21 UTCEG score recompute
- 2026-09-24 03:26 UTCEG score recompute
- 2026-09-24 03:26 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Same CWE
10 shownCWE-1321
Frequently asked(4)
What is CVE-2026-97151?
CVE-2026-97151 is a high vulnerability published on September 24, 2026. mammoth (aka mammoth.js) before 1.12.2 is vulnerable to prototype pollution when reading the styles defined in a document. Converting a crafted .docx file allows an attacker to add arbitrary properties to Object.prototype. In 1.11.0 through 1.12.1, applications that convert further documents in the…
When was CVE-2026-97151 disclosed?
CVE-2026-97151 was first published in the National Vulnerability Database on September 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-97151?
CVE-2026-97151 has a CVSS v3 base score of 8.4 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-97151?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-97151, 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-2026-97151
Is Your Infrastructure Affected by CVE-2026-97151?
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