Out-of-bounds Read in Boazsegev Facil.io

CVE-2026-66729

facil.io 0.6.0 through 0.7.6 contains an integer underflow vulnerability in the multipart MIME body parser that allows unauthenticated remote attackers to crash the server process by sending a crafted Content-Disposition header with an emp…

Vulnerability class: Buffer Overflow

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2026-66729?
CVE-2026-66729 is a high-severity vulnerability in Boazsegev Facil.io, classified under Out-of-bounds Read. CVSS score: 7.5/10. Published 2026-07-27.
How severe is CVE-2026-66729?
High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2026-66729 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.