Vulnerability · Published Oct 12, 2026 · Assigned by VulnCheck
CVE-2026-109380modern-tar 0.3.5 through 0.8.5 Memory Exhaustion via Malformed Octal Size Field
High 7.5
In plain English
A high-severity security flaw in modern-tar from ayuhito. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 39% of all known vulnerabilities).
Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.4%top 61.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
modern-tar 0.3.5 through 0.8.5 contains a memory exhaustion vulnerability that allows attackers to produce negative entry sizes via non-octal bytes parsed by readOctal(). Attackers can supply a crafted, optionally gzip-compressed, archive to unpackTar() that buffers chunks indefinitely, exhausting process memory and suppressing later entries.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| ayuhito | modern-tar | 0.3.5 – through 0.8.5 |
Weakness: CWE-1284 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- GitHub Pull Request #195 issue-tracking, patch
- Patch Commit patch
- Vulnerable code in encoding.ts technical-description
- https://github.com/ayuhito/modern-tar product
- VulnCheck Advisory: modern-tar 0.3.5 through 0.8.5 Memory Exhaustion via Malformed Octal Size Field third-party-advisory