CVE-2026-75421 aria2 CVE debrief

Who should care

Organizations and individuals using aria2 version up to 1.37.0 should be aware of this vulnerability and take necessary actions to mitigate the risk. This includes operators of systems with aria2 installed, security teams responsible for vulnerability management, and platform administrators who may need to apply patches or updates. Those impacted should assess their exposure, apply vendor guidance, and monitor for potential exploitation attempts.

Technical summary

The CVE-2026-75421 vulnerability is a stack-buffer-underflow in the IOFile::getLine() function of aria2, a command-line download utility. This vulnerability has been classified as Medium severity with a CVSS score of 4. The vulnerability was publicly disclosed on 2026-08-25 and last modified on 2026-08-31. Affected systems may experience potential crashes or code execution if exploited. Users of aria2 version up to 1.37.0 should take necessary precautions.

Defensive priority

Medium priority due to the stack-buffer-underflow vulnerability in aria2, a widely used command-line download utility.

Recommended defensive actions

• Inventory and assess usage of aria2 within your organization
• Check for and apply vendor-provided patches or updates
• Monitor for potential exploitation attempts
• Consider compensating controls such as restricting access to aria2

Evidence notes

The CVE record and NVD entry provide evidence of a stack-buffer-underflow vulnerability in aria2 version up to 1.37.0. However, details about the vulnerability's impact and affected configurations are limited. Defenders should verify the presence of aria2 within their environment, assess the version in use, and confirm if the system is exposed to untrusted input. They should also review vendor-provided patches or updates and consider compensating controls.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.