CVE-2026-116738 kisli CVE debrief

Who should care

Defenders responsible for VMime installations, email security, and vulnerability management should assess exposure and prioritize remediation. This includes IT teams managing VMime-based applications, cybersecurity teams responsible for vulnerability management, and email administrators who need to ensure the security of email communications. Additionally, operators of systems using VMime for email processing should be aware of the potential risks and take

Why it matters

CVE-2026-116738 is a high-severity vulnerability in VMime that requires immediate attention from defenders to prevent potential code execution or application crashes.

• Potential code execution or application crashes
• Increased risk of denial-of-service attacks
• Need for input validation and sanitization
• Priority for updating and verifying VMime installations

Technical summary

The uuEncoder::decode function in VMime through 0.9.2 contains an integer underflow that can be exploited to trigger a stack-based buffer overflow. This can be done by sending an email with a crafted uuencoded MIME part, potentially leading to application crashes or code execution. The vulnerability is caused by an integer underflow in the uuEncoder::decode function, which can lead to a stack-based buffer overflow. This issue affects VMime versions up to 0.9.2 and requires immediate attention from defenders to prevent potential code execution or application crashes.

Defensive priority

Defenders should prioritize verifying and updating VMime installations to prevent potential code execution or application crashes.

Recommended defensive actions

• Verify and update VMime installations to the latest version
• Implement input validation and sanitization for uuencoded MIME parts
• Monitor for suspicious email activity
• Consider implementing compensating controls to detect and prevent exploitation
• Review and update incident response plans to address potential exploitation
• Conduct vulnerability scanning and risk assessments to identify exposed systems
• Develop and implement a patch management process to ensure timely updates

Evidence notes

The vulnerability is caused by an integer underflow in the uuEncoder::decode function, which can lead to a stack-based buffer overflow. This issue affects VMime versions up to 0.9.2. The integer underflow occurs when the uuEncoder::decode function is called with a crafted uuencoded MIME part, potentially leading to application crashes or code execution. Defenders should verify and update VMime installations to the latest version and implement input validation and sanitization for uuencoded MIME parts.

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.