CVE-2026-73258
MEDIUMDescription
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 accept dangerous content after seeing a misleading Content-Type value. This issue is fixed in version 7.22.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Exploit Intelligence
Low risk: more likely to be exploited than 19% of all known CVEs.
References
Related Vulnerabilities
Other CWE-697 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2024-5217 | Critical | 9.8 | 100% | KEV | - |
| CVE-2020-5849 | High | 7.5 | 93% | KEV | - |
| CVE-2020-8864 | High | 8.8 | 80% | - | - |
| CVE-2025-3102 | High | 8.1 | 76% | - | - |
| CVE-2023-32571 | Critical | 9.8 | 35% | - | - |
| CVE-2020-8862 | High | 8.8 | 13% | - | - |
Common questions
How do I fix CVE-2026-73258?
Upgrade mongoose on debian unstable to 7.22+ds-1 or later.
Is CVE-2026-73258 being actively exploited?
Not that we know of. CVE-2026-73258 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.27% is the estimated probability that it will be exploited in the next 30 days. That is higher than 19% of all scored CVEs.
How severe is CVE-2026-73258?
CVE-2026-73258 has a CVSS v3 base score of 6.5, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-73258 affect?
Published advisories record a fix for mongoose (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2026-73258
Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-08-20.