{"id":182539,"date":"2026-07-08T10:54:16","date_gmt":"2026-07-08T08:54:16","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/bad-epoll-v-linux-i-android-nashli-uyazvimost-dlya-polucheniya-root-dostupa"},"modified":"2026-07-08T10:54:16","modified_gmt":"2026-07-08T08:54:16","slug":"bad-epoll-v-linux-i-android-nashli-uyazvimost-dlya-polucheniya-root-dostupa","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/news\/bad-epoll-v-linux-i-android-nashli-uyazvimost-dlya-polucheniya-root-dostupa","title":{"rendered":"Bad Epoll: nalezena zranitelnost v Linuxu a Androidu pro z\u00edsk\u00e1n\u00ed root p\u0159\u00edstupu","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

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1 <\/p>\n

V j\u00e1dru Linux byla odhalena zranitelnost \u0160patn\u00fd Epoll<\/strong>, registrovan\u00e1 jako CVE-2026-46242<\/a>. Umo\u017e\u0148uje b\u011b\u017en\u00e9mu m\u00edstn\u00edmu u\u017eivateli bez speci\u00e1ln\u00edch opr\u00e1vn\u011bn\u00ed zv\u00fd\u0161it privilegium na \u00farove\u0148 root. Podle autora v\u00fdzkumu Jaeona Chonga, tento probl\u00e9m se t\u00fdk\u00e1 nejen Linux desktop\u016f a server\u016f, ale tak\u00e9 \u010d\u00e1sti za\u0159\u00edzen\u00ed Android na nov\u00fdch verz\u00edch j\u00e1dra \u2014 to je zvl\u00e1\u0161\u0165 zd\u016frazn\u011bno v popisu Bad Epoll<\/a>.<\/p>\n

<\/noindex> <\/p>\n

Chyba se nach\u00e1z\u00ed v subsyst\u00e9mu epoll<\/strong> \u2014 standardn\u00ed mechanismus Linuxu pro sledov\u00e1n\u00ed mnoha popisova\u010d\u016f soubor\u016f, s\u00ed\u0165ov\u00fdch p\u0159ipojen\u00ed a ud\u00e1lost\u00ed vstupu\/v\u00fdstupu. Tyto mechanismy aktivn\u011b pou\u017e\u00edvaj\u00ed servery, prohl\u00ed\u017ee\u010de a s\u00ed\u0165ov\u00e9 slu\u017eby, proto nen\u00ed mo\u017en\u00e9 jednodu\u0161e epoll zak\u00e1zat. V technick\u00e9 anal\u00fdze<\/a> je zranitelnost pops\u00e1na jako z\u00e1vod, vedouc\u00ed k use-after-free<\/strong>: p\u0159i sou\u010dasn\u00e9m uzav\u0159en\u00ed souvisej\u00edc\u00edch epoll objekt\u016f jeden vl\u00e1kno uvol\u0148uje vnit\u0159n\u00ed struktury, zat\u00edmco druh\u00e9 k nim st\u00e1le p\u0159istupuje.<\/p>\n

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P\u0159esn\u011bji \u0159e\u010deno, probl\u00e9m se projevuje ve situaci, kdy jeden epoll popisova\u010d sleduje druh\u00fd, a oba popisova\u010de jsou uzav\u0159eny paraleln\u011b. Po zavol\u00e1n\u00ed __ep_remove() se pole file->f_ep do\u010dasn\u011b nastav\u00ed na nulovou hodnotu, a konkuren\u010dn\u00ed __fput() m\u016f\u017ee usoudit, \u017ee dal\u0161\u00ed \u00fadr\u017eba ji\u017e nen\u00ed pot\u0159ebn\u00e1. V\u00fdsledkem je, \u017ee objekt struct eventpoll nebo s n\u00edm spojen\u00fd struct file je uvoln\u011bn p\u0159\u00edli\u0161 brzy, ale k\u00f3d st\u00e1le pracuje s ukazateli na ji\u017e uvoln\u011bnou pam\u011b\u0165. To d\u00e1v\u00e1 \u00fato\u010dn\u00edkovi primitiv pro po\u0161kozov\u00e1n\u00ed pam\u011bti j\u00e1dra.<\/p>\n

<\/p>\n

Pro \u00fatok nejsou pot\u0159eba dal\u0161\u00ed opr\u00e1vn\u011bn\u00ed a nejsou vy\u017eadov\u00e1ny u\u017eivatelsk\u00e9 namespaces \u2014 sta\u010d\u00ed m\u00edt CONFIG_EPOLL, co\u017e \u010din\u00ed probl\u00e9m obzvl\u00e1\u0161\u0165 nep\u0159\u00edjemn\u00fdm pro b\u011b\u017en\u00e9 Linuxov\u00e9 syst\u00e9my. Podle po\u010d\u00e1te\u010dn\u00ed zpr\u00e1vy v\u00fdzkumn\u00edka<\/a>, chyba byla zanesena do j\u00e1dra commitem 58c9b016e128<\/a> v roce 2023, a opravena commitem a6dc643c693<\/a>.<\/p>\n

<\/noindex> <\/p>\n

I p\u0159es velmi \u00fazk\u00e9 okno z\u00e1vodu, v\u00fdzkumn\u00edk p\u0159ipravil funk\u010dn\u00ed exploit pro Google kernelCTF. V popisu exploitace<\/a> je uk\u00e1z\u00e1no, jak chyba p\u0159ech\u00e1z\u00ed na 8-bytov\u00fd z\u00e1pis do uvoln\u011bn\u00e9 struktury, pot\u00e9 na \u00fanik pam\u011bti j\u00e1dra p\u0159es \/proc\/self\/fdinfo, z\u00e1chyt file->f_op->poll a ROP \u0159et\u011bzec pro z\u00edsk\u00e1n\u00ed root. Pro c\u00edl lts-6.12.67 je uvedena spolehlivost asi 99%, pro COS \u2014 kolem 98%; Android exploit, podle autora, je je\u0161t\u011b ve st\u00e1diu pr\u00e1ce.<\/p>\n

<\/noindex> <\/p>\n

Pod \u00fatokem jsou j\u00e1dra zalo\u017een\u00e1 na v\u011btvi 6.4 a nov\u011bj\u0161\u00ed<\/strong>, pokud nebyla opravena. Star\u0161\u00ed Android za\u0159\u00edzen\u00ed na j\u00e1drech 6.1, v\u010detn\u011b Pixel 8 a podobn\u00fdch model\u016f, autor pova\u017euje za nezraniteln\u00e1<\/a>. U\u017eivatel\u00e9 a administr\u00e1to\u0159i maj\u00ed k dispozici pouze jednu rozumnou mo\u017enost ochrany \u2014 nainstalovat aktualizaci j\u00e1dra od sv\u00e9ho distribuce nebo dodavatele za\u0159\u00edzen\u00ed.<\/p>\n

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Zdroj: linux.org.ru<\/a><\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

1 \u0412 \u044f\u0434\u0440\u0435 Linux \u0440\u0430\u0441\u043a\u0440\u044b\u0442\u0430 \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c Bad Epoll, \u0437\u0430\u0440\u0435\u0433\u0438\u0441\u0442\u0440\u0438\u0440\u043e\u0432\u0430\u043d\u043d\u0430\u044f \u043a\u0430\u043a CVE-2026-46242. \u041e\u043d\u0430 \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u0435\u0442 \u043e\u0431\u044b\u0447\u043d\u043e\u043c\u0443 \u043b\u043e\u043a\u0430\u043b\u044c\u043d\u043e\u043c\u0443 \u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u0435\u043b\u044e \u0431\u0435\u0437 \u0441\u043f\u0435\u0446\u0438\u0430\u043b\u044c\u043d\u044b\u0445 \u043f\u0440\u0430\u0432 \u043f\u043e\u0432\u044b\u0441\u0438\u0442\u044c \u043f\u0440\u0438\u0432\u0438\u043b\u0435\u0433\u0438\u0438 \u0434\u043e root. \u041f\u043e \u0434\u0430\u043d\u043d\u044b\u043c \u0430\u0432\u0442\u043e\u0440\u0430 \u0438\u0441\u0441\u043b\u0435\u0434\u043e\u0432\u0430\u043d\u0438\u044f \u0414\u0436\u044d\u0451\u043d\u0430 \u0427\u043e\u043d\u0430, \u043f\u0440\u043e\u0431\u043b\u0435\u043c\u0430 \u0437\u0430\u0442\u0440\u0430\u0433\u0438\u0432\u0430\u0435\u0442 \u043d\u0435 \u0442\u043e\u043b\u044c\u043a\u043e Linux-\u0434\u0435\u0441\u043a\u0442\u043e\u043f\u044b \u0438 \u0441\u0435\u0440\u0432\u0435\u0440\u044b, \u043d\u043e \u0438 \u0447\u0430\u0441\u0442\u044c Android-\u0443\u0441\u0442\u0440\u043e\u0439\u0441\u0442\u0432 \u043d\u0430 \u043d\u043e\u0432\u044b\u0445 \u0432\u0435\u0440\u0441\u0438\u044f\u0445 \u044f\u0434\u0440\u0430 \u2014 \u044d\u0442\u043e \u043e\u0442\u0434\u0435\u043b\u044c\u043d\u043e \u043f\u043e\u0434\u0447\u0451\u0440\u043a\u0438\u0432\u0430\u0435\u0442\u0441\u044f \u0432 \u043e\u043f\u0438\u0441\u0430\u043d\u0438\u0438 Bad Epoll. \u041e\u0448\u0438\u0431\u043a\u0430 \u043d\u0430\u0445\u043e\u0434\u0438\u0442\u0441\u044f \u0432 […]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":9,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[702],"tags":[],"class_list":["post-182539","post","type-post","status-publish","format-standard","hentry","category-news"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\n","aioseo_head_json":{"title":"\ud83e\udd47\u0160patn\u00fd Epoll: V Linuxu a Androidu byla nalezena zranitelnost umo\u017e\u0148uj\u00edc\u00ed z\u00edsk\u00e1n\u00ed root p\u0159\u00edstupu | 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