Buffer overflow in Kisli Vmime
CVE-2026-116738
VMime through 0.9.2 contains an integer underflow in the uuEncoder::decode function that allows remote attackers to trigger a stack-based buffer overflow via crafted uuencoded MIME parts. Attackers can send an email with a uuencoded line whose length character is 'b' but is not a 'begin' line, corrupting stack memory to crash the application or potentially execute code.
Vulnerability class: Buffer Overflow
Published .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/kisli/vmime/pull/363 (issue-tracking, patch)
- github.com/kisli/vmime/commit/e85925eddc638939f0eeb7ee55ec047d04a760d8 (patch)
- github.com/kisli/vmime (product)
- github.com/kisli/vmime/blob/v0.9.2/src/vmime/utility/encoder/uuEncoder.cpp (technical-description)
- hackmd.io/@haindpwn/vmime-uuencode-decoder-oob-write (third-party-advisory)
- www.vulncheck.com/advisories/vmime-through-0.9.2-stack-based-buffer-overflow-vi… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-116738?
- CVE-2026-116738 is a high-severity vulnerability in Kisli Vmime, classified under Stack-based Buffer Overflow. CVSS score: 8.8/10. Published 2026-10-26.
- How severe is CVE-2026-116738?
- High severity. CVSS v3 base score is 8.8 out of 10.