CVE-2021-45960
HIGHEPSS 90th pctlDescription
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).
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Exploit Intelligence
High risk: more likely to be exploited than 90% of all known CVEs.
References
Related Vulnerabilities
Other CWE-682 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2022-30780 | High | 7.5 | 56% | - | Fix |
| CVE-2020-14422 | Medium | 5.9 | 13% | - | Fix |
| CVE-2016-7433 | Medium | 5.3 | 9.8% | - | Fix |
| CVE-2023-35641 | High | 8.8 | 7.2% | - | Fix |
| CVE-2018-8319 | Critical | 9.8 | 7.0% | - | - |
| CVE-2020-0022 | High | 8.8 | 6.1% | - | Fix |
Common questions
How do I fix CVE-2021-45960?
Published advisories record a fix for 12 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.
Is CVE-2021-45960 being actively exploited?
Not that we know of. CVE-2021-45960 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 4.2% is the estimated probability that it will be exploited in the next 30 days. That is higher than 90% of all scored CVEs.
How severe is CVE-2021-45960?
CVE-2021-45960 has a CVSS v3 base score of 8.8, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2021-45960 affect?
Published advisories record a fix for expat (Debian), expat (Red Hat / RHEL), expat (Rocky), expat-debuginfo (Red Hat / RHEL), and 8 more. Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-05-05.