CVE-2021-28040
An uncontrolled recursion vulnerability in os_xml.c occurs when a large number of opening and closing XML tags is used.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.19%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 1.19% probability · 68th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-674
- Affected
- ossec/ossec
- Source
- cve@mitre.org
EPSS 1.2% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/ossec/ossec-hids/issues/1953Exploit, Issue Tracking, Third Party Advisory
- https://github.com/ossec/ossec-hids/issues/1953Exploit, Issue Tracking, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.