CVE-2021-28040
CVSS v3
7.5
HIGH
EPSS Score
1.2 %
exploit probability, as of 2026-09-25
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Description
An issue was discovered in OSSEC 3.6.0. An uncontrolled recursion vulnerability in os_xml.c occurs when a large number of opening and closing XML tags is used. Because recursion is used in _ReadElem without restriction, an attacker can trigger a segmentation fault once unmapped memory is reached.
Technical details
- Published
- 2021-03-05
Frequently asked questions
What is CVE-2021-28040?
An issue was discovered in OSSEC 3.6.0. An uncontrolled recursion vulnerability in os_xml.c occurs when a large number of opening and closing XML tags is used. Because recursion is used in _ReadElem without restriction, an attacker can trigger a segmentation fault once unmapped memory is reached.
Is CVE-2021-28040 actively exploited?
Active exploitation of CVE-2021-28040 has not been confirmed. Its EPSS score was 1.2% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2021-28040?
CVE-2021-28040 has a CVSS v3 base score of 7.5 (HIGH severity).
Is CVE-2021-28040 affecting your environment?
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