Vulnerability · Published Nov 4, 2026 · Assigned by GitHub_M

CVE-2026-115473Mongoose: Heap OOB reads and null-byte bypass in mg_path_is_sane (util.c)

Medium 6.5

In plain English

A medium-severity out-of-bounds read in mongoose from cesanta. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 18% of all known vulnerabilities).

Severity (CVSS 3.1)6.5Medium

Exploit odds (30 days)0.3%top 81.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

Vendor	Product	Versions
cesanta	mongoose	< 7.22

Weakness: CWE-125, CWE-158 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

References

https://github.com/cesanta/mongoose/security/advisories/GHSA-cjmx-764f-286c x_refsource_CONFIRM
https://github.com/cesanta/mongoose/commit/b55de8b151d1466a3e41d1f854f22eeb6faa23dc x_refsource_MISC
https://github.com/cesanta/mongoose/releases/tag/7.22 x_refsource_MISC