7.7 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
LOW
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L
6.8 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:N/AC:M/Au:N/C:P/I:P/A:P
0.38 Low
EPSS
Percentile
96.6%
Official announcement: http://mailman.nginx.org/pipermail/nginx-announce/2021/000300.html
A security issue in nginx resolver was identified, which might allow an
attacker to cause 1-byte memory overwrite by using a specially crafted
DNS response, resulting in worker process crash or, potentially, in
arbitrary code execution (CVE-2021-23017).
The issue only affects nginx if the “resolver” directive is used in
the configuration file. Further, the attack is only possible if an
attacker is able to forge UDP packets from the DNS server.
The issue affects nginx 0.6.18 - 1.20.0.
The issue is fixed in nginx 1.21.0, 1.20.1.
Patch for the issue can be found here:
http://nginx.org/download/patch.2021.resolver.txt
Thanks to Luis Merino, Markus Vervier, Eric Sesterhenn, X41 D-Sec GmbH.
Crash or, potentially, arbitrary code execution.
7.7 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
LOW
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L
6.8 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:N/AC:M/Au:N/C:P/I:P/A:P
0.38 Low
EPSS
Percentile
96.6%