Thekelleys: >> Dnsmasq >> 2.9 Security Vulnerabilities
A flaw was found in dnsmasq before 2.83. A buffer overflow vulnerability was discovered in the way dnsmasq extract names from DNS packets before validating them with DNSSEC data. An attacker on the network, who can create valid DNS replies, could use this flaw to cause an overflow with arbitrary data in a heap-allocated memory, possibly executing code on the machine. The flaw is in the rfc1035.c:extract_name() function, which writes data to the memory pointed by name assuming MAXDNAME*2 bytes are available in the buffer. However, in some code execution paths, it is possible extract_name() gets passed an offset from the base buffer, thus reducing, in practice, the number of available bytes that can be written in the buffer. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
CVSS Score
8.1
EPSS Score
0.708
Published
2021-01-20
A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in dnsmasq when DNSSEC is enabled and before it validates the received DNS entries. A remote attacker, who can create valid DNS replies, could use this flaw to cause an overflow in a heap-allocated memory. This flaw is caused by the lack of length checks in rfc1035.c:extract_name(), which could be abused to make the code execute memcpy() with a negative size in get_rdata() and cause a crash in dnsmasq, resulting in a denial of service. The highest threat from this vulnerability is to system availability.
CVSS Score
5.9
EPSS Score
0.86
Published
2021-01-20
A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq checks in the forward.c:reply_query() if the reply destination address/port is used by the pending forwarded queries. However, it does not use the address/port to retrieve the exact forwarded query, substantially reducing the number of attempts an attacker on the network would have to perform to forge a reply and get it accepted by dnsmasq. This issue contrasts with RFC5452, which specifies a query's attributes that all must be used to match a reply. This flaw allows an attacker to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25685 or CVE-2020-25686, the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.
CVSS Score
3.7
EPSS Score
0.04
Published
2021-01-20
A flaw was found in dnsmasq before version 2.83. When getting a reply from a forwarded query, dnsmasq checks in forward.c:reply_query(), which is the forwarded query that matches the reply, by only using a weak hash of the query name. Due to the weak hash (CRC32 when dnsmasq is compiled without DNSSEC, SHA-1 when it is) this flaw allows an off-path attacker to find several different domains all having the same hash, substantially reducing the number of attempts they would have to perform to forge a reply and get it accepted by dnsmasq. This is in contrast with RFC5452, which specifies that the query name is one of the attributes of a query that must be used to match a reply. This flaw could be abused to perform a DNS Cache Poisoning attack. If chained with CVE-2020-25684 the attack complexity of a successful attack is reduced. The highest threat from this vulnerability is to data integrity.
CVSS Score
3.7
EPSS Score
0.022
Published
2021-01-20
A vulnerability was found in dnsmasq before version 2.81, where the memory leak allows remote attackers to cause a denial of service (memory consumption) via vectors involving DHCP response creation.
CVSS Score
3.7
EPSS Score
0.027
Published
2020-01-07
Improper bounds checking in Dnsmasq before 2.76 allows an attacker controlled DNS server to send large DNS packets that result in a read operation beyond the buffer allocated for the packet, a different vulnerability than CVE-2017-14491.
CVSS Score
7.5
EPSS Score
0.017
Published
2019-08-01
A vulnerability was found in the implementation of DNSSEC in Dnsmasq up to and including 2.78. Wildcard synthesized NSEC records could be improperly interpreted to prove the non-existence of hostnames that actually exist.
CVSS Score
7.5
EPSS Score
0.026
Published
2018-01-23
Heap-based buffer overflow in dnsmasq before 2.78 allows remote attackers to cause a denial of service (crash) or execute arbitrary code via a crafted DNS response.
CVSS Score
9.8
EPSS Score
0.849
Published
2017-10-04
Heap-based buffer overflow in dnsmasq before 2.78 allows remote attackers to cause a denial of service (crash) or execute arbitrary code via a crafted IPv6 router advertisement request.
CVSS Score
9.8
EPSS Score
0.933
Published
2017-10-03
Stack-based buffer overflow in dnsmasq before 2.78 allows remote attackers to cause a denial of service (crash) or execute arbitrary code via a crafted DHCPv6 request.
CVSS Score
9.8
EPSS Score
0.836
Published
2017-10-03