CVE-2021-33574
CVSS v3
9.8
CRITICAL
EPSS Score
2.9 %
exploit probability, as of 2026-09-25
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Description
The mq_notify function in the GNU C Library (aka glibc) versions 2.32 and 2.33 has a use-after-free. It may use the notification thread attributes object (passed through its struct sigevent parameter) after it has been freed by the caller, leading to a denial of service (application crash) or possibly unspecified other impact.
Technical details
- Published
- 2021-05-25
Frequently asked questions
What is CVE-2021-33574?
The mq_notify function in the GNU C Library (aka glibc) versions 2.32 and 2.33 has a use-after-free. It may use the notification thread attributes object (passed through its struct sigevent parameter) after it has been freed by the caller, leading to a denial of service (application crash) or possibly unspecified other impact.
Is CVE-2021-33574 actively exploited?
Active exploitation of CVE-2021-33574 has not been confirmed. Its EPSS score was 2.9% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2021-33574?
CVE-2021-33574 has a CVSS v3 base score of 9.8 (CRITICAL severity).
Is CVE-2021-33574 affecting your environment?
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