CVE-2021-36173 json
A heap-based buffer overflow in the firmware signature verification function of FortiOS versions 7.0.1, 7.0.0, 6.4.0 through 6.4.6, 6.2.0 t…
published 2021-12-08 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-22794
- cvss
- 8.0
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.5%
- EPSS 1.5% chance of exploitation in 30 days, percentile 75%
- public exploits
- 0
- none known
Summary
A heap-based buffer overflow in the firmware signature verification function of FortiOS versions 7.0.1, 7.0.0, 6.4.0 through 6.4.6, 6.2.0 through 6.2.9, and 6.0.0 through 6.0.13 may allow an attacker to execute arbitrary code via specially crafted installation images.
Patch / fix
- fortiguard.com/advisory/FG-IR-21-115 advisory
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
- Assessed
- 2 y ago
Exploit prediction
1.55% chance of exploitation in the next 30 days, higher than 75% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 8.0 | CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:P/RL:W/RC:C |
| CNA | 3.1 | 8.0 | CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
| NVD | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
| NVD | 2.0 | 6.8 | AV:N/AC:M/Au:N/C:P/I:P/A:P |
Affected products
- Fortinet Fortinet FortiOS
Classification
- Weakness
-
- CWE-787 Out-of-bounds Write
- Technology feeds
References
-
fortiguard.com
/advisory/FG-IR-21-115
patch, vendor-advisory
Sources
- CVE List CVE-2021-36173
- NVD CVE-2021-36173
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.