CVE-2021-40540

CRITICAL 9.8CVE-2021-40540 · Published 07/09/2021 · updated 17/06/2026

In short

CVE-2021-40540 is a CRITICAL (CVSS 9.8) vulnerability affecting ulfius (ulfius project).
Chance of exploitation in the next 30 days (EPSS): 2.6%, higher than 85.6% of all vulnerabilities.
Fix: update to 2.7.4 or later.

Package	Affected versions	Patched versions
ulfius ulfius_project	`< 2.7.4`	`2.7.4`

Description

ulfius_uri_logger in Ulfius HTTP Framework before 2.7.4 omits con_info initialization and a con_info->request NULL check for certain malformed HTTP requests.

References

packetstormsecurity.com/files/164152/Ulfius-Web-Framework-Remote-Memory-Corruption.html · Exploit
babelouest/ulfius commit c83f564 · Patch
babelouest/ulfius · Patch

Running one of these products? Scan your site to see whether it exposes a vulnerable version.

Scan my site free