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.

Red Hat Product Security has been made aware of a stack-based buffer overflow affecting the DHCP implementation of dnsmasq.

DISPUTED Dnsmasq 2.86 has a heap-based buffer overflow in answerrequest (called from FuzzAnswerTheRequest and fuzzrfc1035.c). NOTE: the vendor's position is that CVE-2021-45951 through CVE-2021-45957 "do not represent real vulnerabilities, to the best of our knowledge."

DISPUTED Dnsmasq 2.86 has a heap-based buffer overflow in printmac (called from logpacket and dhcpreply). NOTE: the vendor's position is that CVE-2021-45951 through CVE-2021-45957 "do not represent real vulnerabilities, to the best of our knowledge."

DISPUTED Dnsmasq 2.86 has a heap-based buffer overflow in extractname (called from answerauth and FuzzAuth). NOTE: the vendor's position is that CVE-2021-45951 through CVE-2021-45957 "do not represent real vulnerabilities, to the best of our knowledge."

DISPUTED Dnsmasq 2.86 has a heap-based buffer overflow in resizepacket (called from FuzzResizePacket and fuzzrfc1035.c) because of the lack of a proper bounds check upon pseudo header re-insertion. NOTE: the vendor's position is that CVE-2021-45951 through CVE-2021-45957 "do not represent real vulnerabilities, to the best of our knowledge." However, a contributor states that a security patch (mentioned in 016162.html) is needed.

DISPUTED Dnsmasq 2.86 has a heap-based buffer overflow in extractname (called from hashquestions and fuzzutil.c). NOTE: the vendor's position is that CVE-2021-45951 through CVE-2021-45957 "do not represent real vulnerabilities, to the best of our knowledge."

DISPUTED Dnsmasq 2.86 has a heap-based buffer overflow in dhcpreply (called from dhcppacket and FuzzDhcp). NOTE: the vendor's position is that CVE-2021-45951 through CVE-2021-45957 "do not represent real vulnerabilities, to the best of our knowledge."

DISPUTED Dnsmasq 2.86 has a heap-based buffer overflow in checkbadaddress (called from checkforboguswildcard and FuzzCheckForBogusWildcard). NOTE: the vendor's position is that CVE-2021-45951 through CVE-2021-45957 "do not represent real vulnerabilities, to the best of our knowledge."

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.

A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in the way RRSets are sorted before validating with DNSSEC data. An attacker on the network, who can forge DNS replies such as that they are accepted as valid, could use this flaw to cause a buffer overflow with arbitrary data in a heap memory segment, possibly executing code on the machine. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

A buffer overflow vulnerability was discovered in the way dnsmasq extract names from DNS packets before validating them with DNSSEC data. An attacker, 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 rfc1035.c:extractname() function, which writes data to the memory pointed by name assuming MAXDNAME2 bytes are available in the buffer. However, in some code execution paths it is possible extractname() gets passed an offset from the base buffer, thus reducing in practice the number of available bytes that can be written in the buffer.

dnsmasq 2.25 allows remote attackers to cause a denial of service (daemon crash) by (1) renewing a nonexistent lease or (2) sending a DHCPREQUEST for an IP address that is not in the same network, related to the DHCP NAK response from the daemon.

Integer underflow in the addpseudoheader function in dnsmasq before 2.78 , when the --add-mac, --add-cpe-id or --add-subnet option is specified, allows remote attackers to cause a denial of service via a crafted DNS request.

Certain DNSSEC aspects of the DNS protocol (in RFC 4033, 4034, 4035, 6840, and related RFCs) allow remote attackers to cause a denial of service (CPU consumption) via one or more DNSSEC responses, aka the "KeyTrap" issue. One of the concerns is that, when there is a zone with many DNSKEY and RRSIG records, the protocol specification implies that an algorithm must evaluate all combinations of DNSKEY and RRSIG records.

dnsmasq 2.9 is vulnerable to Integer Overflow via forwardquery.

Dnsmasq before 2.21 allows remote attackers to poison the DNS cache via answers to queries that were not made by Dnsmasq.

Memory leak in dnsmasq before 2.78, when the --add-mac, --add-cpe-id or --add-subnet option is specified, allows remote attackers to cause a denial of service (memory consumption) via vectors involving DNS response creation.

Dnsmasq before 2.76 allows remote servers to cause a denial of service (crash) via a reply with an empty DNS address that has an (1) A or (2) AAAA record defined locally.

In dnsmasq before 2.78, if the DNS packet size does not match the expected size, the size parameter in a memset call gets a negative value. As it is an unsigned value, memset ends up writing up to 0xffffffff zero's (0xffffffffffffffff in 64 bit platforms), making dnsmasq crash.

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.

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.

A flaw was found in dnsmasq. A heap use after free issue in the dhcp6 server may lead to remote denial of service via crafted packet.

References:

https://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2022q1/016272.html

An issue was discovered in Dnsmasq before 2.90. The default maximum EDNS.0 UDP packet size was set to 4096 but should be 1232 because of DNS Flag Day 2020.

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. This flaw allows a remote attacker, who can create valid DNS replies, to cause an overflow in a heap-allocated memory. This flaw is caused by the lack of length checks in rfc1035.c:extractname(), which could be abused to make the code execute memcpy() with a negative size in sortrrset() and cause a crash in dnsmasq, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

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:extractname(), which could be abused to make the code execute memcpy() with a negative size in getrdata() and cause a crash in dnsmasq, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

Core Security Technologies discovered a heap overflow vulnerability in dnsmasq when the TFTP service is enabled ('--enable-tftp'). If the configured tftp-prefix is sufficiently long, and a remote user sent a request which sends a long file name, dnsmasq could crash or, possibly, execute arbitrary code with root privileges.

The default tftp-prefix is /var/tftpd, which is short enough to make this difficult to exploit; if a longer prefix is used then arbitrary code execution may be possible. As well, Red Hat does not have TFTP support enabled by default.

The tcprequest function in Dnsmasq before 2.73rc4 does not properly handle the return value of the setupreply function, which allows remote attackers to read process memory and cause a denial of service (out-of-bounds read and crash) via a malformed DNS request.

A heap buffer overflow exists in dnsmasq's logquery() function (src/cache.c). When query logging is enabled and dnsmasq logs DS or DNSKEY replies containing unsupported algorithm or digest types, the "(not supported)" suffix causes sprintf() to write past the end of daemon->addrbuff, a 46-byte heap buffer. Trigger example: a DS record with keytag=65535, algorithm=255, digesttype=255 (both algorithm 255 and digesttype 255 are IANA-unassigned), causing the "(not supported)" branch in dnssec.c to fire during logging. Prerequisites: - DNSSEC validation enabled - Query logging enabled (e.g. --log-queries) Impact: bounded heap write overflow (~12 bytes). Upstream maintainer Simon Kelley notes the overwrite is of bounded length, the bytes written are not attacker-controlled, and this is not considered a likely remote-execution vector. Practical impact is denial of service via process crash or heap corruption. Fixed upstream in commit 36d081e37477027fd721fea498f3760f529034ad (dnsmasq 2.92rel2).

dnsmasq before 2.78, when configured as a relay, allows remote attackers to obtain sensitive memory information via vectors involving handling DHCPv6 forwarded requests.