PatchTheCVECVE-2026-73258: Mongoose is an embedded web server and network library
CVE-2026-73258 is a medium-severity flaw (CVSS 6.5) affecting mongoose. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
Mongoose is an embedded web server and network library. Prior to 7.22, a remote attacker can place a lone carriage return or line feed in multipart input processed by mg_http_next_multipart() in src/http.c. The loops comparing s[b] and s[b + 1], and s[h2] and s[h2 + 1], use an incorrect AND condition and stop when either character resembles part of a CRLF terminator. This truncates headers, filenames, or boundaries and can cause an application to
Why this priority
- Public exploit reference
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 6.5 (Medium) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.5% (top 60%) |
| CISA exploited list | No |
| Weakness | CWE-697 |
| Published | 2026-08-20 |
| Last modified | 2026-10-18 |
Last updated 2026-10-18 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-73258?
mongoose: upgrade to 7.22. Exact commands for each OS are on this page.
Is CVE-2026-73258 being exploited?
CVE-2026-73258 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-73258 affect?
CVE-2026-73258 affects mongoose. Severity is medium (CVSS 6.5). Mongoose is an embedded web server and network library. Prior to 7.22, a remote attacker can place a lone carriage return or line feed in multipart input processed by mg_http_next_multipart() in src/http.c. The loops comparing s[b] and s[b
How urgent is CVE-2026-73258?
Priority 43/100. Public exploit reference; Remotely exploitable, no login, no user action
Related CVEs
- CVE-2026-5244 HIGH 7.3 UPGRADE A vulnerability has been found in Cesanta Mongoose up to 7.20
- CVE-2026-6985 MEDIUM 5.3 UPGRADE A weakness has been identified in Cesanta Mongoose up to 7.20
- CVE-2026-5246 MEDIUM 5.6 UPGRADE A vulnerability was determined in Cesanta Mongoose up to 7.20
- CVE-2026-5245 MEDIUM 5.6 UPGRADE A vulnerability was found in Cesanta Mongoose up to 7.20
- CVE-2026-6986 LOW 3.7 UPGRADE A security vulnerability has been detected in Cesanta Mongoose up to 7.20