# CVE-2026-71832: Aria2 divide by zero in bittorrent_helper

Source: https://junglewise.ai/threats/cve-2026-71832-aria2-divide-by-zero-in-bittorrent-helper  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-24. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-71832 · Severity: medium · CVSS 6.2 · Published 2026-08-24

Aria2 is a popular open-source download manager used to transfer files over the internet. A flaw in how it parses torrent files allows an attacker to craft a malicious torrent that causes the application to crash when processed, disrupting download operations and potentially the systems running Aria2.

## Quick answers

**Is CVE-2026-71832 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-71832 being exploited in the wild.

**How severe is CVE-2026-71832?** Medium severity, with a CVSS score of 6.2, published 24 August 2026.

**Which products and versions are affected?** Aria2 Project Aria2 1.37.0 and below.

**Is there a fix for CVE-2026-71832?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-71832 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-71832?** Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A divide-by-zero vulnerability exists in src/bittorrent_helper.cc, specifically in the processRootDictionary function. The flaw occurs when parsing a malicious torrent file where the pieceLength field is set to zero, which is then used as a divisor in a calculation without validation. An attacker can craft a malicious .torrent file and provide it to a user or service running Aria2; when the file is processed, the division-by-zero triggers an undefined behavior sanitizer error and causes a crash (Floating Point Exception). No authentication is required; the attack is triggered simply by providing a malicious torrent file to the application.

## Affected products

- Aria2 Project Aria2 1.37.0 and below

## Timeline

- 2026-07-28: disclosed: Issue reported on GitHub
- 2026-08-24: advisory: CVE published

## References

- [https://github.com/aria2/aria2/issues/2371](https://github.com/aria2/aria2/issues/2371)