PatchTheCVECVE-2021-38408: A stack-based buffer overflow vulnerability in Advantech WebAccess Versions 9.02 and prior caused by a lack of
CVE-2021-38408 is a critical-severity flaw (CVSS 9.8) affecting webaccess. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
A stack-based buffer overflow vulnerability in Advantech WebAccess Versions 9.02 and prior caused by a lack of proper validation of the length of user-supplied data may allow remote code execution.
Why this priority
- Critical severity
- EPSS top 4%: very likely to be exploited
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 9.8 (Critical) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 11.6% (top 4%) |
| CISA exploited list | No |
| Weakness | CWE-121 |
| Published | 2021-09-09 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · 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-2021-38408?
webaccess: upgrade to newer than 9.02. Exact commands for each OS are on this page.
Is CVE-2021-38408 being exploited?
CVE-2021-38408 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-2021-38408 affect?
CVE-2021-38408 affects webaccess. Severity is critical (CVSS 9.8). A stack-based buffer overflow vulnerability in Advantech WebAccess Versions 9.02 and prior caused by a lack of proper validation of the length of user-supplied data may allow remote code execution.
How urgent is CVE-2021-38408?
Priority 63/100. Critical severity; EPSS top 4%: very likely to be exploited; Remotely exploitable, no login, no user action
Software pages
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