{"id":"CVE-2021-23351","aliases":["DEBIAN-CVE-2021-23351","EUVD-2021-1065","GHSA-fqh4-rh59-xhvf","SNYK-GOLANG-GITHUBCOMPIRESGOPROXYPROTO-1081577","UBUNTU-CVE-2021-23351"],"status":"published","title":"Denial of Service (DoS)","description":"The package github.com/pires/go-proxyproto before 0.5.0 are vulnerable to Denial of Service (DoS) via the parseVersion1() function. The reader in this package is a default bufio.Reader wrapping a net.Conn. It will read from the connection until it finds a newline. Since no limits are implemented in the code, a deliberately malformed V1 header could be used to exhaust memory in a server process using this code - and create a DoS. This can be exploited by sending a stream starting with PROXY and continuing to send data (which does not contain a newline) until the target stops acknowledging. The risk here is small, because only trusted sources should be allowed to send proxy protocol headers.","severity":{"version":"3.1","score":4.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.01871,"percentile":0.79637,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-400"],"published":"2021-03-08T04:45:23Z","modified":"2026-10-23T18:04:49Z","fixes":[{"ecosystem":"Go","package":"github.com/pires/go-proxyproto","fixed_in":["0.5.0"],"sources":["ghsa","osv"]},{"ecosystem":"Debian:12","package":"golang-github-pires-go-proxyproto","fixed_in":["0.4.2-1"],"sources":["osv"]},{"ecosystem":"Debian:13","package":"golang-github-pires-go-proxyproto","fixed_in":["0.4.2-1"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"golang-github-pires-go-proxyproto","fixed_in":["0.4.2-1"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"Go","package":"github.com/pires/go-proxyproto","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.5.0"}]}]},{"source":"osv","ecosystem":"Debian:12","package":"golang-github-pires-go-proxyproto","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.4.2-1"}]}]},{"source":"osv","ecosystem":"Debian:13","package":"golang-github-pires-go-proxyproto","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.4.2-1"}]}]},{"source":"osv","ecosystem":"Debian:14","package":"golang-github-pires-go-proxyproto","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.4.2-1"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/pires/go-proxyproto","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.5.0"}]}]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"golang-github-pires-go-proxyproto","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.4.2-1"]}],"products":[{"vendor":"fedoraproject","product":"fedora"},{"vendor":"go-proxyproto_project","product":"go-proxyproto"}],"references":[{"url":"https://snyk.io/vuln/SNYK-GOLANG-GITHUBCOMPIRESGOPROXYPROTO-1081577","tags":["x_refsource_MISC","x_transferred","Third Party Advisory","advisory","web","report"]},{"url":"https://github.com/pires/go-proxyproto/pull/71","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory","fix","web","report"]},{"url":"https://github.com/pires/go-proxyproto/issues/69","tags":["x_refsource_MISC","x_transferred","Third Party Advisory","advisory","web","report"]},{"url":"https://github.com/pires/go-proxyproto/commit/7f48261db810703d173f27f3309a808cc2b49b8b","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory","fix","web","report"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4BNVGJMVI3ZTZ675EFPUHPGXCKCGSX46/","tags":["vendor-advisory","x_refsource_FEDORA","x_transferred","web"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/C36IBVOZXRTWM7MGTRUTOM56P5RR74VU/","tags":["vendor-advisory","x_refsource_FEDORA","x_transferred","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-23351","tags":["advisory"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4BNVGJMVI3ZTZ675EFPUHPGXCKCGSX46/"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/C36IBVOZXRTWM7MGTRUTOM56P5RR74VU/"},{"url":"https://github.com/advisories/GHSA-fqh4-rh59-xhvf"},{"url":"https://security-tracker.debian.org/tracker/CVE-2021-23351","tags":["advisory"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4BNVGJMVI3ZTZ675EFPUHPGXCKCGSX46","tags":["web"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/C36IBVOZXRTWM7MGTRUTOM56P5RR74VU","tags":["web"]},{"url":"https://ubuntu.com/security/CVE-2021-23351","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-23351","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2021-23351","title":"Denial of Service (DoS)","description":"The package github.com/pires/go-proxyproto before 0.5.0 are vulnerable to Denial of Service (DoS) via the parseVersion1() function. The reader in this package is a default bufio.Reader wrapping a net.Conn. It will read from the connection until it finds a newline. Since no limits are implemented in the code, a deliberately malformed V1 header could be used to exhaust memory in a server process using this code - and create a DoS. This can be exploited by sending a stream starting with PROXY and continuing to send data (which does not contain a newline) until the target stops acknowledging. The risk here is small, because only trusted sources should be allowed to send proxy protocol headers.","status":"published","published":"2021-03-08T04:45:23.83Z","modified":"2024-09-17T01:31:07.953Z","cvss":[{"version":"3.1","score":4.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna"}],"updated_at":"2026-11-02T14:33:00.488332Z"}],"euvd":[{"id":"EUVD-2021-1065","description":"The package github.com/pires/go-proxyproto before 0.5.0 are vulnerable to Denial of Service (DoS) via the parseVersion1() function. The reader in this package is a default bufio.Reader wrapping a net.Conn. It will read from the connection until it finds a newline. Since no limits are implemented in the code, a deliberately malformed V1 header could be used to exhaust memory in a server process using this code - and create a DoS. This can be exploited by sending a stream starting with PROXY and continuing to send data (which does not contain a newline) until the target stops acknowledging. The risk here is small, because only trusted sources should be allowed to send proxy protocol headers.","status":"published","published":"2021-03-08T04:45:23Z","modified":"2024-09-17T01:31:07Z","cvss":[{"version":"3.1","score":4.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-03T00:28:48.901339Z"}],"ghsa":[{"id":"GHSA-fqh4-rh59-xhvf","title":"github.com/pires/go-proxyproto denial of service vulnerability","description":"The package `github.com/pires/go-proxyproto` before 0.5.0 are vulnerable to Denial of Service (DoS) via the `parseVersion1()` function. The reader in this package is a default `bufio.Reader` wrapping a `net.Conn`. It will read from the connection until it finds a newline. Since no limits are implemented in the code, a deliberately malformed V1 header could be used to exhaust memory in a server process using this code - and create a DoS. This can be exploited by sending a stream starting with PROXY and continuing to send data (which does not contain a newline) until the target stops acknowledging. The risk here is small, because only trusted sources should be allowed to send proxy protocol headers.","status":"published","published":"2021-05-18T21:07:43Z","modified":"2023-09-14T19:22:34Z","cvss":[{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-400"],"updated_at":"2026-11-02T14:37:05.567008Z"}],"nvd":[{"id":"CVE-2021-23351","description":"The package github.com/pires/go-proxyproto before 0.5.0 are vulnerable to Denial of Service (DoS) via the parseVersion1() function. The reader in this package is a default bufio.Reader wrapping a net.Conn. It will read from the connection until it finds a newline. Since no limits are implemented in the code, a deliberately malformed V1 header could be used to exhaust memory in a server process using this code - and create a DoS. This can be exploited by sending a stream starting with PROXY and continuing to send data (which does not contain a newline) until the target stops acknowledging. The risk here is small, because only trusted sources should be allowed to send proxy protocol headers.","status":"published","published":"2021-03-08T05:15:12.593Z","modified":"2026-06-17T03:38:36.22Z","cvss":[{"version":"3.1","score":4.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"secondary"},{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"primary"},{"version":"2.0","score":4,"vector":"AV:N/AC:L/Au:S/C:N/I:N/A:P","level":"medium","assessor":"primary"}],"updated_at":"2026-11-02T14:06:50.399901Z"}],"osv":[{"id":"CVE-2021-23351","description":"The package github.com/pires/go-proxyproto before 0.5.0 are vulnerable to Denial of Service (DoS) via the parseVersion1() function. The reader in this package is a default bufio.Reader wrapping a net.Conn. It will read from the connection until it finds a newline. Since no limits are implemented in the code, a deliberately malformed V1 header could be used to exhaust memory in a server process using this code - and create a DoS. This can be exploited by sending a stream starting with PROXY and continuing to send data (which does not contain a newline) until the target stops acknowledging. The risk here is small, because only trusted sources should be allowed to send proxy protocol headers.","status":"published","published":"2021-03-08T05:15:12.593Z","modified":"2026-10-20T10:54:32.439219211Z","cvss":[{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:44:18.367807Z"},{"id":"DEBIAN-CVE-2021-23351","description":"The package github.com/pires/go-proxyproto before 0.5.0 are vulnerable to Denial of Service (DoS) via the parseVersion1() function. The reader in this package is a default bufio.Reader wrapping a net.Conn. It will read from the connection until it finds a newline. Since no limits are implemented in the code, a deliberately malformed V1 header could be used to exhaust memory in a server process using this code - and create a DoS. This can be exploited by sending a stream starting with PROXY and continuing to send data (which does not contain a newline) until the target stops acknowledging. The risk here is small, because only trusted sources should be allowed to send proxy protocol headers.","status":"published","published":"2021-03-08T05:15:12.593Z","modified":"2026-10-23T18:04:49.907402013Z","cvss":[{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:45:34.637046Z"},{"id":"GHSA-fqh4-rh59-xhvf","title":"github.com/pires/go-proxyproto denial of service vulnerability","description":"The package `github.com/pires/go-proxyproto` before 0.5.0 are vulnerable to Denial of Service (DoS) via the `parseVersion1()` function. The reader in this package is a default `bufio.Reader` wrapping a `net.Conn`. It will read from the connection until it finds a newline. Since no limits are implemented in the code, a deliberately malformed V1 header could be used to exhaust memory in a server process using this code - and create a DoS. This can be exploited by sending a stream starting with PROXY and continuing to send data (which does not contain a newline) until the target stops acknowledging. The risk here is small, because only trusted sources should be allowed to send proxy protocol headers.","status":"published","published":"2021-05-18T21:07:43Z","modified":"2026-07-08T06:49:45.6065965Z","cvss":[{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-400"],"updated_at":"2026-11-02T15:46:46.760785Z"},{"id":"UBUNTU-CVE-2021-23351","description":"The package github.com/pires/go-proxyproto before 0.5.0 are vulnerable to Denial of Service (DoS) via the parseVersion1() function. The reader in this package is a default bufio.Reader wrapping a net.Conn. It will read from the connection until it finds a newline. Since no limits are implemented in the code, a deliberately malformed V1 header could be used to exhaust memory in a server process using this code - and create a DoS. This can be exploited by sending a stream starting with PROXY and continuing to send data (which does not contain a newline) until the target stops acknowledging. The risk here is small, because only trusted sources should be allowed to send proxy protocol headers.","status":"published","published":"2021-03-08T05:15:00Z","modified":"2025-09-08T16:46:59Z","cvss":[{"version":"3.1","score":4.4,"vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium"},{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-02T15:54:26.779273Z"}]}}