Security readout for executives and security teams
CVE-2021-23017 is a memory overwrite flaw in the nginx DNS resolver. An attacker who can forge UDP packets appearing to come from the configured DNS server may crash nginx worker processes, with sources noting possible other impact. Business risk is highest where affected nginx versions sit on internet-facing or high-availability services. Exposure is likely where affected nginx or NGINX Plus versions are deployed and the nginx resolver is in use. Downstream packaged deployments may also matter, as Fedora, Oracle, F5, and NetApp references appear in the source bundle. Prioritize remediation for exposed production nginx services because the credible outcome includes service disruption. The evidence does not support claiming active exploitation, but affected versions are old and fixed releases are available. Mitigation focus: Upgrade nginx to 1.20.1 or later where applicable.; Upgrade NGINX Plus R23 to R23 P1 or R24 to R24 P1.; Check downstream vendor advisories for packaged or embedded nginx builds..
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
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CWE-193: Exact CWE lookup
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Open ATT&CK lookupCVE-2021-23017 mapping review
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Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
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CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://support.f5.com/csp/article/K12331123%2CCVE reference · x_refsource_MISC
- [apisix-notifications] 20210607 [GitHub] [apisix-website] Serendipity96 opened a new pull request #362: feat: add new blogCVE reference · mailing-list, x_refsource_MLIST
- [apisix-notifications] 20210608 [GitHub] [apisix-website] liuxiran commented on a change in pull request #362: docs: added "Apache APISIX not affected by NGINX CVE-2021-23017"CVE reference · mailing-list, x_refsource_MLIST
- [apisix-notifications] 20210608 [GitHub] [apisix-website] netlify[bot] edited a comment on pull request #362: docs: added "Apache APISIX not affected by NGINX CVE-2021-23017"CVE reference · mailing-list, x_refsource_MLIST
- [apisix-notifications] 20210608 [GitHub] [apisix-website] liuxiran merged pull request #362: docs: added "Apache APISIX not affected by NGINX CVE-2021-23017"CVE reference · mailing-list, x_refsource_MLIST
- [apisix-notifications] 20210608 [apisix-website] branch master updated: docs: added "Apache APISIX not affected by NGINX CVE-2021-23017" (#362)CVE reference · mailing-list, x_refsource_MLIST
- FEDORA-2021-b37cffac0dCVE reference · vendor-advisory, x_refsource_FEDORA
- FEDORA-2021-393d698493CVE reference · vendor-advisory, x_refsource_FEDORA
- https://www.oracle.com/security-alerts/cpuoct2021.htmlCVE reference · x_refsource_MISC
- https://security.netapp.com/advisory/ntap-20210708-0006/CVE reference · x_refsource_CONFIRM
- https://www.oracle.com/security-alerts/cpujan2022.htmlCVE reference · x_refsource_MISC
- https://www.oracle.com/security-alerts/cpuapr2022.htmlCVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Off-by-one Error
Off-by-one Error represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.