CVE-2021-23017
A security issue in nginx resolver was identified, which might allow an attacker who is able to forge UDP packets from the DNS server to cause 1-byte memory overwrite, resulting in worker process crash or potential other impact.
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 53.5%, higher than 99% of all known CVEs. Patch or mitigate before the next change window.
Description
A security issue in nginx resolver was identified, which might allow an attacker who is able to forge UDP packets from the DNS server to cause 1-byte memory overwrite, resulting in worker process crash or potential other impact.
- CVSS 3.1
- 7.7 HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L
- EPSS
- 53.46% probability · 99th percentile
- Public exploits
- 1 in Exploit-DB · first 11 July 2022
- CISA KEV
- Not listed
- Weakness
- CWE-193
- Affected
- f5/nginx · openresty/openresty · fedoraproject/fedora · netapp/ontap select deploy administration utility · oracle/blockchain platform · oracle/communications control plane monitor · oracle/communications fraud monitor · oracle/communications operations monitor · oracle/communications session border controller · oracle/enterprise communications broker · oracle/enterprise session border controller · oracle/enterprise telephony fraud monitor · oracle/goldengate
- Source
- f5sirt@f5.com
EPSS 53.5% since 3 November 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
Public exploits (1)
Entries in Exploit-DB that cite this CVE. Links go to the Exploit-DB page and to the file in the public repository; nothing is hosted here. A verified tick means the Exploit-DB team confirmed the exploit works against the stated version.
References
- http://mailman.nginx.org/pipermail/nginx-announce/2021/000300.htmlMailing List, Patch, Vendor Advisory
- http://packetstormsecurity.com/files/167720/Nginx-1.20.0-Denial-Of-Service.htmlThird Party Advisory, VDB Entry
- https://lists.apache.org/thread.html/r37e6b2165f7c910d8e15fd54f4697857619ad2625f56583802004009%40%3Cnotifications.apisix.apache.org%3E
- https://lists.apache.org/thread.html/r4d4966221ca399ce948ef34884652265729d7d9ef8179c78d7f17e7f%40%3Cnotifications.apisix.apache.org%3E
- https://lists.apache.org/thread.html/r6fc5c57b38e93e36213e9a18c8a4e5dbd5ced1c7e57f08a1735975ba%40%3Cnotifications.apisix.apache.org%3E
- https://lists.apache.org/thread.html/rf232eecd47fdc44520192810560303073cefd684b321f85e311bad31%40%3Cnotifications.apisix.apache.org%3E
- https://lists.apache.org/thread.html/rf318aeeb4d7a3a312734780b47de83cefb7e6995da0b2cae5c28675c%40%3Cnotifications.apisix.apache.org%3E
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7SFVYHC7OXTEO4SMBWXDVK6E5IMEYMEE/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GNKOP2JR5L7KCIZTJRZDCUPJTUONMC5I/
- https://security.netapp.com/advisory/ntap-20210708-0006/Third Party Advisory
- https://support.f5.com/csp/article/K12331123%2C
- https://www.oracle.com/security-alerts/cpuapr2022.htmlPatch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpujan2022.htmlPatch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpuoct2021.htmlPatch, Third Party Advisory
- http://mailman.nginx.org/pipermail/nginx-announce/2021/000300.htmlMailing List, Patch, Vendor Advisory
- http://packetstormsecurity.com/files/167720/Nginx-1.20.0-Denial-Of-Service.htmlThird Party Advisory, VDB Entry
- https://lists.apache.org/thread.html/r37e6b2165f7c910d8e15fd54f4697857619ad2625f56583802004009%40%3Cnotifications.apisix.apache.org%3E
- https://lists.apache.org/thread.html/r4d4966221ca399ce948ef34884652265729d7d9ef8179c78d7f17e7f%40%3Cnotifications.apisix.apache.org%3E
- https://lists.apache.org/thread.html/r6fc5c57b38e93e36213e9a18c8a4e5dbd5ced1c7e57f08a1735975ba%40%3Cnotifications.apisix.apache.org%3E
- https://lists.apache.org/thread.html/rf232eecd47fdc44520192810560303073cefd684b321f85e311bad31%40%3Cnotifications.apisix.apache.org%3E
- https://lists.apache.org/thread.html/rf318aeeb4d7a3a312734780b47de83cefb7e6995da0b2cae5c28675c%40%3Cnotifications.apisix.apache.org%3E
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7SFVYHC7OXTEO4SMBWXDVK6E5IMEYMEE/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GNKOP2JR5L7KCIZTJRZDCUPJTUONMC5I/
- https://security.netapp.com/advisory/ntap-20210708-0006/Third Party Advisory
- https://support.f5.com/csp/article/K12331123%2C
- https://www.oracle.com/security-alerts/cpuapr2022.htmlPatch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpujan2022.htmlPatch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpuoct2021.htmlPatch, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.