CVE-2021-20325
Published: 18 February 2022
Summary
CVE-2021-20325 is a critical-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Redhat Enterprise Linux. Its CVSS base score is 9.8 (Critical).
Operationally, ranked in the top 23.4% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-7748
Vulnerability details
Missing fixes for CVE-2021-40438 and CVE-2021-26691 in the versions of httpd, as shipped in Red Hat Enterprise Linux 8.5.0, causes a security regression compared to the versions shipped in Red Hat Enterprise Linux 8.4. A user who installs or updates…
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to Red Hat Enterprise Linux 8.5.0 would be vulnerable to the mentioned CVEs, even if they were properly fixed in Red Hat Enterprise Linux 8.4. CVE-2021-20325 was assigned to that Red Hat specific security regression and it does not affect the upstream versions of httpd.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Memory protections (e.g., W^X, ASLR) make exploitation of buffer-boundary violations far harder to turn into code execution.
Detects exploitation attempts that produce memory corruption, crashes, or anomalous behavior.
Penetration testing attempts server-side requests to internal resources, identifying SSRF weaknesses for remediation.
Ongoing control assessments and code testing (static/dynamic analysis, fuzzing) surface memory buffer restriction failures, which are then remediated before release.
Managed runtimes used by platform-independent applications (e.g., JVM, CLR) enforce memory safety, preventing most buffer overflows that require direct memory manipulation.
Outbound connections to external resources can be monitored and limited at the boundary, reducing SSRF impact.
Validates server-side URLs and resource references to block SSRF attempts.