|Number of vulnerabilities||1|
|CVE ID|| CVE-2021-23017
|CWE ID|| CWE-193
|Public exploit||Public exploit code for vulnerability #1 is available.|
Red Hat Software Collections
Universal components / Libraries / Software for developers
rh-nginx116-nginx (Red Hat package)
Operating systems & Components / Operating system package or component
|Vendor||Red Hat Inc.|
This security advisory describes one high risk vulnerability.
CVSSv3.1: 7.3 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C] [PCI]
CWE-193 - Off-by-one Error
Exploit availability: YesDescription
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to an off-by-one error within the
ngx_resolver_copy() function when processing DNS responses. A remote attacker can trigger an off-by-one error, write a dot character (‘.’, 0x2E) out of bounds in a heap allocated buffer and execute arbitrary code on the system.
Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.
The vulnerability can be triggered by a DNS response in reply to a DNS request from nginx when the resolver primitive is configured. A specially crafted packet allows overwriting the least significant byte of next heap chunk metadata with 0x2E.Mitigation
Install updates from vendor's website.
Red Hat Software Collections: 1 for RHEL 7, 1 for RHEL 7.7
rh-nginx116-nginx (Red Hat package): before 1.16.1-6.el7CPE
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.