CVE-2026-109380 modern-tar 0.3.5 through 0.8.5 Memory Exhaustion via Malformed Octal Size Field
Attackers can cause memory exhaustion and denial of service in modern-tar by supplying a crafted archive with malformed octal size fields.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-109380?
CVE-2026-109380 is a high-severity denial of service vulnerability in ayuhito modern-tar, published on 12 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-1284
Which versions are affected by CVE-2026-109380?
How do I fix CVE-2026-109380?
No fix has been published for CVE-2026-109380 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-109380 being exploited?
There is no known exploitation of CVE-2026-109380 in the wild and no public exploit code.
Sources
Also known as GHSA-m6wr-6wgx-82mm.