{"id":"CVE-2021-45955","aliases":["AZL-8962","BELL-CVE-2021-45955","EUVD-2021-32662","GHSA-p5g5-mjp3-mr9m"],"status":"disputed","title":"Dnsmasq 2.86 has a heap-based buffer overflow in resize_packet (called from FuzzResizePacket and...","description":"Dnsmasq 2.86 has a heap-based buffer overflow in resize_packet (called from FuzzResizePacket and fuzz_rfc1035.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","severity":{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-10","score":0.02602,"percentile":0.85493,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-787"],"published":"2021-12-31T23:53:42Z","modified":"2026-06-17T04:14:19Z","fixes":[{"ecosystem":"Azure Linux:2","package":"dnsmasq","fixed_in":["2.89-2"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Azure Linux:2","package":"dnsmasq","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.89-2"}]}]}],"products":[{"vendor":"thekelleys","product":"dnsmasq"}],"references":[{"url":"https://github.com/google/oss-fuzz-vulns/blob/main/vulns/dnsmasq/OSV-2021-932.yaml","tags":["x_refsource_MISC","x_transferred","Third Party Advisory"]},{"url":"https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=35898","tags":["x_refsource_MISC","x_transferred","Exploit","Issue Tracking","Third Party Advisory"]},{"url":"https://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2022q1/016162.html","tags":["x_refsource_MISC","x_transferred","Mailing List","Third Party Advisory"]},{"url":"https://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2022q1/016164.html","tags":["x_refsource_MISC","x_transferred","Mailing List","Third Party Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-45955","tags":["web"]},{"url":"https://github.com/advisories/GHSA-p5g5-mjp3-mr9m"},{"url":"https://docs.bell-sw.com/security/cves/CVE-2021-45955","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2021-45955","description":"Dnsmasq 2.86 has a heap-based buffer overflow in resize_packet (called from FuzzResizePacket and fuzz_rfc1035.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","status":"disputed","published":"2021-12-31T23:53:42Z","modified":"2024-08-04T04:54:31.055Z","updated_at":"2026-11-02T14:33:02.930115Z"}],"euvd":[{"id":"EUVD-2021-32662","description":"Dnsmasq 2.86 has a heap-based buffer overflow in resize_packet (called from FuzzResizePacket and fuzz_rfc1035.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","status":"published","published":"2021-12-31T23:53:42Z","modified":"2024-08-04T04:54:31Z","updated_at":"2026-11-03T03:08:25.222984Z"}],"ghsa":[{"id":"GHSA-p5g5-mjp3-mr9m","title":"Dnsmasq 2.86 has a heap-based buffer overflow in resize_packet (called from FuzzResizePacket and...","description":"Dnsmasq 2.86 has a heap-based buffer overflow in resize_packet (called from FuzzResizePacket and fuzz_rfc1035.c).","status":"published","published":"2022-01-02T00:00:58Z","modified":"2023-02-03T05:03:48Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-787"],"updated_at":"2026-11-02T14:53:25.886002Z"}],"nvd":[{"id":"CVE-2021-45955","description":"Dnsmasq 2.86 has a heap-based buffer overflow in resize_packet (called from FuzzResizePacket and fuzz_rfc1035.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","status":"disputed","published":"2022-01-01T00:15:08.677Z","modified":"2026-06-17T04:14:19.143Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary"},{"version":"2.0","score":7.5,"vector":"AV:N/AC:L/Au:N/C:P/I:P/A:P","level":"high","assessor":"primary"}],"cwes":["CWE-787"],"updated_at":"2026-11-02T14:07:02.977492Z"}],"osv":[{"id":"AZL-8962","title":"CVE-2021-45955 affecting package dnsmasq for versions less than 2.89-2","description":"Dnsmasq 2.86 has a heap-based buffer overflow in resize_packet (called from FuzzResizePacket and fuzz_rfc1035.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","status":"published","published":"2022-01-01T00:15:08Z","modified":"2026-04-21T04:34:56.302084Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T15:28:11.397546Z"},{"id":"BELL-CVE-2021-45955","title":"CVE-2021-45955 does not affect BellSoft software","status":"withdrawn","published":"2022-01-01T00:15:00Z","modified":"2026-01-26T10:04:54.309964Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T15:28:16.5265Z"}]}}