{"id":"CVE-2021-43824","details":"Envoy is an open source edge and service proxy, designed for cloud-native applications. In affected versions a crafted request crashes Envoy when a CONNECT request is sent to JWT filter configured with regex match. This provides a denial of service attack vector. The only workaround is to not use regex in the JWT filter. Users are advised to upgrade.","aliases":["BIT-envoy-2021-43824"],"modified":"2026-04-11T23:37:18.177781Z","published":"2022-02-22T23:15:10.813Z","related":["GHSA-vj5m-rch8-5r2p"],"references":[{"type":"REPORT","url":"https://github.com/envoyproxy/envoy/security/advisories/GHSA-vj5m-rch8-5r2p"},{"type":"FIX","url":"https://github.com/envoyproxy/envoy/commit/9371333230b1a6e1be2eccf4868771e11af6253a"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/envoyproxy/envoy","events":[{"introduced":"0"},{"fixed":"a79ca225f1ed924b855dff8a26bd7f7cdb84e694"},{"introduced":"68fe53a889416fd8570506232052b06f5a531541"},{"fixed":"a17cdcdfad24de101e95716b77549ba689824f25"},{"introduced":"96701cb24611b0f3aac1cc0dd8bf8589fbdf8e9e"},{"fixed":"4aaf9593152c6996b9da384c8918e9ad4f0abd4d"},{"introduced":"a9d72603c68da3a10a1c0d021d01c7877e6f2a30"},{"fixed":"af50070ee60866874b0a9383daf9364e884ded22"},{"fixed":"9371333230b1a6e1be2eccf4868771e11af6253a"}],"database_specific":{"versions":[{"introduced":"0"},{"fixed":"1.18.6"},{"introduced":"1.19.0"},{"fixed":"1.19.3"},{"introduced":"1.20.0"},{"fixed":"1.20.2"},{"introduced":"1.21.0"},{"fixed":"1.21.1"}]}}],"versions":["v1.0.0","v1.1.0","v1.10.0","v1.11.0","v1.12.0","v1.13.0","v1.14.0","v1.15.0","v1.16.0","v1.17.0","v1.18.0","v1.18.1","v1.18.2","v1.18.3","v1.18.4","v1.19.0","v1.19.1","v1.2.0","v1.20.0","v1.20.1","v1.21.0","v1.3.0","v1.4.0","v1.5.0","v1.6.0","v1.7.0","v1.8.0","v1.9.0"],"database_specific":{"vanir_signatures_modified":"2026-04-11T23:37:18Z","vanir_signatures":[{"signature_version":"v1","deprecated":false,"signature_type":"Line","id":"CVE-2021-43824-097fed22","target":{"file":"source/common/tcp_proxy/tcp_proxy.h"},"source":"https://github.com/envoyproxy/envoy/commit/af50070ee60866874b0a9383daf9364e884ded22","digest":{"line_hashes":["245673340480709380475607110780385137708","285494569074532567258474565032572094364","121492910522987967398570563042373873103","208903825150298770882316003860954195851"],"threshold":0.9}},{"signature_version":"v1","deprecated":false,"signature_type":"Function","id":"CVE-2021-43824-0e4fc27e","target":{"function":"Filter::onUpstreamEvent","file":"source/common/tcp_proxy/tcp_proxy.cc"},"source":"https://github.com/envoyproxy/envoy/commit/a79ca225f1ed924b855dff8a26bd7f7cdb84e694","digest":{"length":711,"function_hash":"63191530169222520921233896458439701262"}},{"signature_version":"v1","deprecated":false,"signature_type":"Line","id":"CVE-2021-43824-21f82a03","target":{"file":"source/extensions/filters/http/jwt_authn/matcher.cc"},"source":"https://github.com/envoyproxy/envoy/commit/9371333230b1a6e1be2eccf4868771e11af6253a","digest":{"line_hashes":["16695513628882731710386236080108344740","226065387100708587604550551532432243880","16435745593053750970339365835642838940","290690702275778456420641259607659362098"],"threshold":0.9}},{"signature_version":"v1","deprecated":false,"signature_type":"Line","id":"CVE-2021-43824-25d456d2","target":{"file":"source/common/tcp_proxy/tcp_proxy.cc"},"source":"https://github.com/envoyproxy/envoy/commit/a17cdcdfad24de101e95716b77549ba689824f25","digest":{"line_hashes":["146243477446113422387021212725253250778","38867459780981627133568037950540228786","247042036583305394760031334831783811398","325013980647195303750429821852338176203","190222441294940987692714025372522320194","233481120278761949454860284316900076892","33182693539138785849824461743826464632","238411867963402661331142337279192022640"],"threshold":0.9}},{"signature_version":"v1","deprecated":false,"signature_type":"Function","id":"CVE-2021-43824-3fe0ae84","target":{"function":"Filter::onDownstreamEvent","file":"source/common/tcp_proxy/tcp_proxy.cc"},"source":"https://github.com/envoyproxy/envoy/commit/a79ca225f1ed924b855dff8a26bd7f7cdb84e694","digest":{"length":648,"function_hash":"243442652017391788382200176589855195754"}},{"signature_version":"v1","deprecated":false,"signature_type":"Line","id":"CVE-2021-43824-49af67d3","target":{"file":"test/integration/tcp_tunneling_integration_test.cc"},"source":"https://github.com/envoyproxy/envoy/commit/a79ca225f1ed924b855dff8a26bd7f7cdb84e694","digest":{"line_hashes":["48555961344162091530114484247512887348","262502622330308196055685632396206527810","44051101608002913249948422506083140770"],"threshold":0.9}},{"signature_version":"v1","deprecated":false,"signature_type":"Line","id":"CVE-2021-43824-4f2f527a","target":{"file":"test/integration/tcp_tunneling_integration_test.cc"},"source":"https://github.com/envoyproxy/envoy/commit/a17cdcdfad24de101e95716b77549ba689824f25","digest":{"line_hashes":["48555961344162091530114484247512887348","262502622330308196055685632396206527810","44051101608002913249948422506083140770"],"threshold":0.9}},{"signature_version":"v1","deprecated":false,"signature_type":"Function","id":"CVE-2021-43824-750e7fbb","target":{"function":"ConnPoolImplBase::checkForIdleAndCloseIdleConnsIfDraining","file":"source/common/conn_pool/conn_pool_base.cc"},"source":"https://github.com/envoyproxy/envoy/commit/4aaf9593152c6996b9da384c8918e9ad4f0abd4d","digest":{"length":338,"function_hash":"43013079311173114698727080572662162328"}},{"signature_version":"v1","deprecated":false,"signature_type":"Line","id":"CVE-2021-43824-75516c6f","target":{"file":"source/common/conn_pool/conn_pool_base.h"},"source":"https://github.com/envoyproxy/envoy/commit/4aaf9593152c6996b9da384c8918e9ad4f0abd4d","digest":{"line_hashes":["238363169343804913942300291017684487943","281075802092293195505541183629950851527","190309091056183134939303314630437286332","1336839216182560585869212455485126136","91854374677920975889051724337189261314","176073550574850004587196271703191506168","54303611712421497849276770032572170236","89596254872871249889385232134194772639","232868586170569298338666905475474416875","68418232771506422252069681807775341343"],"threshold":0.9}},{"signature_version":"v1","deprecated":false,"signature_type":"Function","id":"CVE-2021-43824-8a3c3605","target":{"function":"Filter::onUpstreamEvent","file":"source/common/tcp_proxy/tcp_proxy.cc"},"source":"https://github.com/envoyproxy/envoy/commit/a17cdcdfad24de101e95716b77549ba689824f25","digest":{"length":711,"function_hash":"63191530169222520921233896458439701262"}},{"signature_version":"v1","deprecated":false,"signature_type":"Line","id":"CVE-2021-43824-9c39651a","target":{"file":"test/integration/tcp_tunneling_integration_test.cc"},"source":"https://github.com/envoyproxy/envoy/commit/af50070ee60866874b0a9383daf9364e884ded22","digest":{"line_hashes":["222375982320279527150068471158201686244","165738277750233846199418982723160704713","44051101608002913249948422506083140770"],"threshold":0.9}},{"signature_version":"v1","deprecated":false,"signature_type":"Function","id":"CVE-2021-43824-a6789e61","target":{"function":"Filter::onDownstreamEvent","file":"source/common/tcp_proxy/tcp_proxy.cc"},"source":"https://github.com/envoyproxy/envoy/commit/af50070ee60866874b0a9383daf9364e884ded22","digest":{"length":808,"function_hash":"296559161755360112084384558440136934044"}},{"signature_version":"v1","deprecated":false,"signature_type":"Function","id":"CVE-2021-43824-abeb66c1","target":{"function":"Filter::onDownstreamEvent","file":"source/common/tcp_proxy/tcp_proxy.cc"},"source":"https://github.com/envoyproxy/envoy/commit/a17cdcdfad24de101e95716b77549ba689824f25","digest":{"length":648,"function_hash":"243442652017391788382200176589855195754"}},{"signature_version":"v1","deprecated":false,"signature_type":"Line","id":"CVE-2021-43824-b538155e","target":{"file":"test/extensions/filters/http/jwt_authn/test_common.h"},"source":"https://github.com/envoyproxy/envoy/commit/9371333230b1a6e1be2eccf4868771e11af6253a","digest":{"line_hashes":["115441571730810549079652967827902341184","60438389137165276459256521079623731500","325439369076572620572492726448389973123"],"threshold":0.9}},{"signature_version":"v1","deprecated":false,"signature_type":"Line","id":"CVE-2021-43824-bf50e605","target":{"file":"test/integration/cds_integration_test.cc"},"source":"https://github.com/envoyproxy/envoy/commit/4aaf9593152c6996b9da384c8918e9ad4f0abd4d","digest":{"line_hashes":["97652407307682118633090827808836069896","202222073443799289957911450767890213833","115564202354952612799820744008677299818","100865938374520508671052066897428637482","266358857140130331037141171435995735386","241277250285489246241581928533925069698","112864798336767260895615422020255373801","326344252156913283305823248376635974319","149501076714298581724217944116072240117","20851967513280832025446682514306651511","101660301215173511645125806388931558046","161983258376373368998625288716073445864","125013157627477663648794220335175813129","114297756736507093046297363714182913184","326342629182717535494243166437244508087","129503348076797258550455082149053172774","6063454819406071701935832397149074681","25450544109902264946434894665349483615","14209541420216802153449926603071335280","28083104488430351869423149520385632380","27329837804645812211356628610675816305"],"threshold":0.9}},{"signature_version":"v1","deprecated":false,"signature_type":"Line","id":"CVE-2021-43824-c143ebbc","target":{"file":"source/common/tcp_proxy/tcp_proxy.h"},"source":"https://github.com/envoyproxy/envoy/commit/a17cdcdfad24de101e95716b77549ba689824f25","digest":{"line_hashes":["245673340480709380475607110780385137708","285494569074532567258474565032572094364","189982742750395040949615227195286815818","260972069293896305361331050164952443697"],"threshold":0.9}},{"signature_version":"v1","deprecated":false,"signature_type":"Line","id":"CVE-2021-43824-c4824ee2","target":{"file":"source/common/tcp_proxy/tcp_proxy.cc"},"source":"https://github.com/envoyproxy/envoy/commit/a79ca225f1ed924b855dff8a26bd7f7cdb84e694","digest":{"line_hashes":["146243477446113422387021212725253250778","38867459780981627133568037950540228786","247042036583305394760031334831783811398","325013980647195303750429821852338176203","190222441294940987692714025372522320194","233481120278761949454860284316900076892","33182693539138785849824461743826464632","238411867963402661331142337279192022640"],"threshold":0.9}},{"signature_version":"v1","deprecated":false,"signature_type":"Line","id":"CVE-2021-43824-ce5c4e8e","target":{"file":"test/config/utility.h"},"source":"https://github.com/envoyproxy/envoy/commit/4aaf9593152c6996b9da384c8918e9ad4f0abd4d","digest":{"line_hashes":["150676539833679190158940891882333303963","27409818851555323095073296906901027733","55324179392422643085196396072729602785"],"threshold":0.9}},{"signature_version":"v1","deprecated":false,"signature_type":"Line","id":"CVE-2021-43824-cf3745ce","target":{"file":"source/common/tcp_proxy/tcp_proxy.h"},"source":"https://github.com/envoyproxy/envoy/commit/a79ca225f1ed924b855dff8a26bd7f7cdb84e694","digest":{"line_hashes":["26722413740939448104101388019871754100","285494569074532567258474565032572094364","189982742750395040949615227195286815818","260972069293896305361331050164952443697"],"threshold":0.9}},{"signature_version":"v1","deprecated":false,"signature_type":"Line","id":"CVE-2021-43824-d54b575d","target":{"file":"source/common/tcp_proxy/tcp_proxy.cc"},"source":"https://github.com/envoyproxy/envoy/commit/af50070ee60866874b0a9383daf9364e884ded22","digest":{"line_hashes":["146243477446113422387021212725253250778","48539946143607539866181123457421037495","283468910120726656487263215273247794220","32816829629574534818331468211218975208","167487698232686579647343259536732486616","18932793910309592312745692489877318569","190222441294940987692714025372522320194","233481120278761949454860284316900076892","33182693539138785849824461743826464632","238411867963402661331142337279192022640"],"threshold":0.9}},{"signature_version":"v1","deprecated":false,"signature_type":"Function","id":"CVE-2021-43824-dc8d3820","target":{"function":"ConnPoolImplBase::closeIdleConnectionsForDrainingPool","file":"source/common/conn_pool/conn_pool_base.cc"},"source":"https://github.com/envoyproxy/envoy/commit/4aaf9593152c6996b9da384c8918e9ad4f0abd4d","digest":{"length":528,"function_hash":"83990222759686494038875668905777786185"}},{"signature_version":"v1","deprecated":false,"signature_type":"Function","id":"CVE-2021-43824-efb2c5e4","target":{"function":"Filter::onUpstreamEvent","file":"source/common/tcp_proxy/tcp_proxy.cc"},"source":"https://github.com/envoyproxy/envoy/commit/af50070ee60866874b0a9383daf9364e884ded22","digest":{"length":711,"function_hash":"63191530169222520921233896458439701262"}},{"signature_version":"v1","deprecated":false,"signature_type":"Line","id":"CVE-2021-43824-f0c98cd4","target":{"file":"source/common/conn_pool/conn_pool_base.cc"},"source":"https://github.com/envoyproxy/envoy/commit/4aaf9593152c6996b9da384c8918e9ad4f0abd4d","digest":{"line_hashes":["211063805449318930197667500157467379330","238149429280769817104751274898789662521","155508904057016497276277837828561242331","306263256694188145409853147140795887683","24621026682503930056724633583760538450","210759516705868193041331552012792706907","268100365964683135363265243678321089408","116993638250131326183953285211810091083","57246520075670457973995740670893215413","194433285147185661463287816608904302305","245699478661219870215728951569204544048","286440446911758131586479113237388457926","33382072507043576477734303938545662581","298229981597606534667320296045042459684","173090808602105440099610064642968627733","210942585548006467924962946211585504886","193341038770066763728097793037333651465","340006873902019806079016649741212930377","286206063645562425499514746822691310145","291017590637862723045538078816014658015"],"threshold":0.9}},{"signature_version":"v1","deprecated":false,"signature_type":"Line","id":"CVE-2021-43824-f21ad525","target":{"file":"test/extensions/filters/http/jwt_authn/filter_integration_test.cc"},"source":"https://github.com/envoyproxy/envoy/commit/9371333230b1a6e1be2eccf4868771e11af6253a","digest":{"line_hashes":["13763891093658840408709216253600349407","199331892274894036869438950256051462149","29210709294056896109510237386162307151"],"threshold":0.9}}],"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-43824.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}