{"id":"CVE-2021-43523","details":"In uClibc and uClibc-ng before 1.0.39, incorrect handling of special characters in domain names returned by DNS servers via gethostbyname, getaddrinfo, gethostbyaddr, and getnameinfo can lead to output of wrong hostnames (leading to domain hijacking) or injection into applications (leading to remote code execution, XSS, applications crashes, etc.). In other words, a validation step, which is expected in any stub resolver, does not occur.","modified":"2026-04-11T18:45:39.710576Z","published":"2021-11-10T15:15:12.213Z","references":[{"type":"ADVISORY","url":"https://uclibc-ng.org/"},{"type":"FIX","url":"https://github.com/wbx-github/uclibc-ng/commit/0f822af0445e5348ce7b7bd8ce1204244f31d174"},{"type":"EVIDENCE","url":"https://www.openwall.com/lists/oss-security/2021/11/09/1"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/wbx-github/uclibc-ng","events":[{"introduced":"0"},{"fixed":"98680eec548b921abecc641b70246587ffbbdc0a"},{"fixed":"0f822af0445e5348ce7b7bd8ce1204244f31d174"}],"database_specific":{"versions":[{"introduced":"0"},{"fixed":"1.0.39"}]}}],"versions":["v1.0.0","v1.0.1","v1.0.10","v1.0.11","v1.0.12","v1.0.13","v1.0.14","v1.0.15","v1.0.16","v1.0.17","v1.0.18","v1.0.19","v1.0.2","v1.0.20","v1.0.21","v1.0.22","v1.0.23","v1.0.24","v1.0.25","v1.0.26","v1.0.27","v1.0.28","v1.0.29","v1.0.30","v1.0.31","v1.0.32","v1.0.33","v1.0.34","v1.0.35","v1.0.36","v1.0.37","v1.0.38","v1.0.4","v1.0.5","v1.0.6","v1.0.7","v1.0.8","v1.0.9"],"database_specific":{"vanir_signatures":[{"target":{"file":"libc/inet/resolv.c"},"source":"https://github.com/wbx-github/uclibc-ng/commit/0f822af0445e5348ce7b7bd8ce1204244f31d174","deprecated":false,"id":"CVE-2021-43523-13627d42","digest":{"threshold":0.9,"line_hashes":["149264702995849926995880357077148658418","243810231544876742984716147609756610546","187030675381736448097324690676783753625","100290982701279520762322895167055908560","254510051435418387231807586264706432803","127470599868015528932188807542183778315","238947607400550915323449413440525444659","100291630674831964903902157310892998","151454825748915532144619970068739494951","89856833502807635002347470409707494480","148312366988786653925409142798107704914","339618317688292319097571634859286458989","33363081068604607857297487112370033761","279277696107889254542476767238182568323","8014272486930206910113337858133153610","67404679295335727849053402728486910846","39664672908463604438436562535780125086","74344633561521975023763775821125317541","221091041025799427006518368187122880931","307121273801650420540320388845313791754","125598997618452317981920348047648707664","21760855911259382741492069268857317211","293885711760885308786630919328611396419","215376830079803944236967906711375132863","280789395264276232750830863600257661405","178219953907381805852041282970328377271","242032130722139442784584669633065954461","149298575035780289452995437699480611392","133481329120677515855056248096345088620","167874028530862599751312015329974450094","193298813581817783774239728871110003957","311424175083350137278754627965055219714","207071184630088015915361978077643763745","35112011265620622621068167055770592639","74456878702499903498546084175784394791","32208519443934144979955140749924375756","258172524578157566106918639407807282432","257697376243251966081591258945331191205","148840428707586260763930967901346675651"]},"signature_type":"Line","signature_version":"v1"},{"target":{"function":"gethostbyaddr_r","file":"libc/inet/resolv.c"},"source":"https://github.com/wbx-github/uclibc-ng/commit/0f822af0445e5348ce7b7bd8ce1204244f31d174","deprecated":false,"id":"CVE-2021-43523-95c3f977","digest":{"length":2922,"function_hash":"142910486240576585748756844269932716179"},"signature_type":"Function","signature_version":"v1"},{"target":{"function":"__dns_lookup","file":"libc/inet/resolv.c"},"source":"https://github.com/wbx-github/uclibc-ng/commit/0f822af0445e5348ce7b7bd8ce1204244f31d174","deprecated":false,"id":"CVE-2021-43523-e3aa6a0d","digest":{"length":6923,"function_hash":"162191713996631590485357856097300099751"},"signature_type":"Function","signature_version":"v1"}],"vanir_signatures_modified":"2026-04-11T18:45:39Z","source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-43523.json","unresolved_ranges":[{"events":[{"introduced":"0"},{"last_affected":"0.9.33.2"}]}]}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H"}]}