CVE-2026-116739
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AI Threat Summary
CVE-2026-116739 is a moderate vulnerability with a CVSS score of 4.3 affecting the target software. Threat hunters should monitor for exploit attempts and apply vendor patches immediately.
Description
VMime through 0.9.2 contains an information disclosure vulnerability in the uuEncoder::decode function that writes uninitialized stack memory into decoded output for over-long lines. Attackers can send a crafted uuencode or x-uuencode MIME part with a large line length byte to leak up to 15 bytes of stack contents per line in decoded attachments.
Attack Chain
Attacker scans for vulnerable versions using version banners or PoC scanners
Attacker triggers CVE-2026-116739 vulnerability with a crafted request or payload
Vulnerability exploited to perform unauthorized actions on the target system
Depending on vulnerability type, attacker achieves data access, service disruption, or code execution
MITRE ATT&CK Techniques
Indicators of Compromise
| Type | Value | Description | |
|---|---|---|---|
| user_agent | Mozilla/5.0 (compatible; exploit/1.0) |
Generic exploit scanner user agent pattern | |
| url | /api/vuln-endpoint?payload=<malicious> |
Exploit attempt against application endpoint — monitor access logs for anomalous params |
Remediation
Quick Facts
| CVE ID | CVE-2026-116739 |
| CVSS Score | 4.3 |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N |
| Published | 2026-10-26 |
| Exploited | No |
| CISA KEV | No |
| PoC | Not public |
References
- https://github.com/kisli/vmime
- https://github.com/kisli/vmime/blob/v0.9.2/src/vmime/utility…
- https://github.com/kisli/vmime/commit/e85925eddc638939f0eeb7…
- https://github.com/kisli/vmime/pull/363
- https://hackmd.io/@haindpwn/vmime-uuencode-decoder-oob-write
- https://www.vulncheck.com/advisories/vmime-through-0.9.2-uni…