Out-of-bounds Read in Cesanta Mongoose
CVE-2026-115473
Mongoose is an embedded web server and network library. Prior to 7.22, mg_path_is_sane in src/util.c read path.buf[1] without first requiring path.len to be at least two and read s[2] when only two bytes remained. Unauthenticated remote requests reaching mg_http_upload or mg_http_serve_dir with the affected short path shapes could therefore trigger one-byte heap out-of-bounds reads. On bare-metal or RTOS targets without memory protection, the adjacent byte could be exposed or influence whether a path was accepted, and instrumented builds could crash. This issue is fixed in version 7.22.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L.
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
- Cesanta Mongoose — versions < 7.22
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-115473?
- CVE-2026-115473 is a medium-severity vulnerability in Cesanta Mongoose, classified under Out-of-bounds Read. CVSS score: 6.5/10. Published 2026-11-04.
- How severe is CVE-2026-115473?
- Medium severity. CVSS v3 base score is 6.5 out of 10.