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

Status: published. Published: 2026-11-04. Updated: 2026-11-04.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- cesanta / mongoose: < 7.22 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 3.1: 6.5 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-125, CWE-158

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/cesanta/mongoose/security/advisories/GHSA-cjmx-764f-286c (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/cesanta/mongoose/commit/b55de8b151d1466a3e41d1f854f22eeb6faa23dc (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/cesanta/mongoose/releases/tag/7.22 (CNA: GitHub_M; x_refsource_MISC)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-115473; retrieved 2026-11-04; source updated 2026-11-04

Revision: 8486e2a788456c25044873bb633c46c260833448d387b900304b28e4d5d83f84

Canonical: https://y2.dev/cve/CVE-2026-115473

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