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Fencer Vulns
critical 9.8

CVE-2021-40540 json

ulfius_uri_logger in Ulfius HTTP Framework before 2.7.4 omits con_info initialization and a con_info->request NULL check for certain malfor…

published 2021-09-07 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-27715

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.6%
EPSS 2.6% chance of exploitation in 30 days, percentile 85%
public exploits
0
none known

Summary

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.

Patch / fix

  • ulfius_project ulfius 2.7.4
  • ulfius Debian 14, Debian 13, Debian 12 2.7.1-2

debian advisories DEBIAN-CVE-2021-40540

  • ulfius openSUSE Tumbleweed 2.7.4-1.2

opensuse advisories openSUSE-SU-2024:11481-1

  • ulfius Arch Linux 2.7.4-1

arch linux advisories AVG-2361

Exploit prediction

2.63% chance of exploitation in the next 30 days, higher than 85% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • packetstormsecurity.com http://packetstormsecurity.com/files/164152/Ulfius-Web-Framework-Remote-Memory-Corruption.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

References

Sources

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.