CVE-2021-45960
CVSS v3
8.8
HIGH
EPSS Score
4.2 %
exploit probability, as of 2026-09-25
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Description
In Expat (aka libexpat) before 2.4.3, a left shift by 29 (or more) places in the storeAtts function in xmlparse.c can lead to realloc misbehavior (e.g., allocating too few bytes, or only freeing memory).
Technical details
- Published
- 2022-01-01
Frequently asked questions
What is CVE-2021-45960?
In Expat (aka libexpat) before 2.4.3, a left shift by 29 (or more) places in the storeAtts function in xmlparse.c can lead to realloc misbehavior (e.g., allocating too few bytes, or only freeing memory).
Is CVE-2021-45960 actively exploited?
Active exploitation of CVE-2021-45960 has not been confirmed. Its EPSS score was 4.2% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2021-45960?
CVE-2021-45960 has a CVSS v3 base score of 8.8 (HIGH severity).
Is CVE-2021-45960 affecting your environment?
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