{"id":170699,"date":"2026-05-15T06:24:37","date_gmt":"2026-05-15T04:24:37","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/uyazvimost-v-exim-privodyashhaya-k-udalyonnomu-vypolneniyu-koda-na-servere"},"modified":"2026-05-15T06:24:37","modified_gmt":"2026-05-15T04:24:37","slug":"uyazvimost-v-exim-privodyashhaya-k-udalyonnomu-vypolneniyu-koda-na-servere","status":"publish","type":"post","link":"https:\/\/prohoster.info\/sk\/blog\/news\/uyazvimost-v-exim-privodyashhaya-k-udalyonnomu-vypolneniyu-koda-na-servere","title":{"rendered":"Zranite\u013enos\u0165 v Exim, ktor\u00e1 vedie k vzdialen\u00e9mu vykonaniu k\u00f3du na serveri","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Na po\u0161tovom serveri Exim bola zisten\u00e1 kritick\u00e1 zranite\u013enos\u0165 (CVE-2026-45185), ktor\u00e1 umo\u017e\u0148uje vzdialen\u00e9 vykonanie k\u00f3du na serveri. Probl\u00e9m sa prejavuje od vetvy Exim 4.97 pri zostaven\u00ed s kni\u017enicou GnuTLS («USE_GNUTLS=yes») a bol odstr\u00e1nen\u00fd vo verzii Exim 4.99.3. Zostavy s OpenSSL a in\u00fdmi kni\u017enicami, ktor\u00e9 nie s\u00fa GnuTLS, nie s\u00fa touto zranite\u013enos\u0165ou ovplyvnen\u00e9. <\/p>\n

Probl\u00e9m je sp\u00f4soben\u00fd pr\u00edstupom k u\u017e uvo\u013enenej pam\u00e4ti (use-after-free) v backende k GnuTLS a m\u00f4\u017ee by\u0165 zneu\u017eit\u00fd pri pr\u00edstupoch na servery, ktor\u00e9 podporuj\u00fa roz\u0161\u00edrenie «ESMTP CHUNKING» a pr\u00edkaz BDAT na prenos \u010dast\u00ed tela spr\u00e1vy namiesto prenosu ako jedn\u00e9ho bloku pomocou pr\u00edkazu DATA. Po\u0161kodenie obsahu pam\u00e4te procesu nast\u00e1va pri iniciovan\u00ed pred\u010dasn\u00e9ho ukon\u010denia rel\u00e1cie TLS klientom pomocou pr\u00edkazu close_notify po\u010das prenosu tela spr\u00e1vy cez BDAT a n\u00e1slednom odoslan\u00ed jedn\u00e9ho bajtu bez \u0161ifrovania v otvorenej forme v rovnakom TCP spojen\u00edm. <\/p>\n

Po prijat\u00ed pr\u00edkazu close_notify v backendovom GnuTLS sa vol\u00e1 funkcia preru\u0161enia TLS rel\u00e1cie, ktor\u00e1 uvo\u013e\u0148uje s\u00favisiace buffre so rel\u00e1ciou. V d\u00f4sledku chyby v k\u00f3de backendu napriek uvo\u013eneniu TLS buffra spracovate\u013e BDAT pokra\u010duje v \u010d\u00edtan\u00ed d\u00e1t z pr\u00fadu a vol\u00e1 funkciu ungetc(), \u010do pri odoslan\u00ed potom nezak\u00f3dovan\u00fdch d\u00e1t vedie k zap\u00edsaniu jedn\u00e9ho bajtu do u\u017e uvo\u013enen\u00e9ho buffra. Tento bajt po\u0161kodzuje metadata alok\u00e1tora pam\u00e4te v hromade (heap), \u010do bolo pou\u017eit\u00e9 na vykonanie experimentov na vytvorenie exploitov, ktor\u00e9 vykon\u00e1vaj\u00fa \u013eubovo\u013en\u00fd k\u00f3d na. serveri<\/a>. <\/p>\n

Na za\u010diatku vedci vygenerovali \u010diasto\u010dne funk\u010dn\u00fd exploit pomocou AI, ktor\u00fd umo\u017enil vykonanie k\u00f3du, ale bol funk\u010dn\u00fd iba v sklen\u00edkov\u00fdch podmienkach, na syst\u00e9moch s vypnutou ochranou ASLR a PIE a ur\u010dit\u00fdm verziou kni\u017enice libc. N\u00e1sledne sa pok\u00fasili o vytvorenie exploitu za \u00fa\u010dasti \u010dloveka, v ktorom sa podarilo prekona\u0165 niektor\u00e9 \u0165a\u017ekosti a dosiahnu\u0165 \u00fanik adresy z\u00e1sobn\u00edka, av\u0161ak do pl\u00e1novan\u00e9ho d\u00e1tumu zverejnenia inform\u00e1ci\u00ed o zranite\u013enosti nebol exploit dokon\u010den\u00fd. Pod\u013ea n\u00e1zorov vedcov, ktor\u00ed zranite\u013enos\u0165 odhalili, AI asistenti e\u0161te nie s\u00fa schopn\u00ed vytv\u00e1ra\u0165 exploity pre zlo\u017eit\u00e9 produkty, ale d\u00fafaj\u00fa, \u017ee v bud\u00facnosti in\u00ed vedci bud\u00fa schopn\u00ed dokon\u010di\u0165 ich pr\u00e1cu a nap\u00edsa\u0165 plne funk\u010dn\u00fd exploit. <\/p>\n

V\u00e4\u010d\u0161ie distrib\u00facie pou\u017e\u00edva Exim 4.97+ vo svojich verzi\u00e1ch v Debian 13, Ubuntu 24.04+, SUSE\/openSUSE, Arch Linux, Alpine Linux 3.19+, ALT Linux p11, ROSA, Gentoo, OpenWRT, Fedora, EPEL (exim nie je s\u00fa\u010das\u0165ou \u0161tandardn\u00e9ho repozit\u00e1ra RHEL) a FreeBSD. Sestava Exim s GnuTLS sa predvolene pou\u017e\u00edva v Debian a Ubuntu, v in\u00fdch distrib\u00faci\u00e1ch je potrebn\u00e9 objasni\u0165. Ako obch\u00e1dzku blokovania zranite\u013enosti je mo\u017en\u00e9 vypn\u00fa\u0165 roz\u0161\u00edrenie CHUNKING pomocou nastavenia chunking_advertise_hosts v konfigura\u010dnom s\u00fabore.
\n
Zdroj: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u0412 \u043f\u043e\u0447\u0442\u043e\u0432\u043e\u043c \u0441\u0435\u0440\u0432\u0435\u0440\u0435 Exim \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u043a\u0440\u0438\u0442\u0438\u0447\u0435\u0441\u043a\u0430\u044f \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2026-45185), \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u0443\u0434\u0430\u043b\u0451\u043d\u043d\u043e \u0434\u043e\u0431\u0438\u0442\u044c\u0441\u044f \u0432\u044b\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u044f \u043a\u043e\u0434\u0430 \u043d\u0430 \u0441\u0435\u0440\u0432\u0435\u0440\u0435. \u041f\u0440\u043e\u0431\u043b\u0435\u043c\u0430 \u043f\u0440\u043e\u044f\u0432\u043b\u044f\u0435\u0442\u0441\u044f \u043d\u0430\u0447\u0438\u043d\u0430\u044f \u0441 \u0432\u0435\u0442\u043a\u0438 Exim 4.97 \u043f\u0440\u0438 \u0441\u0431\u043e\u0440\u043a\u0435 \u0441 \u0431\u0438\u0431\u043b\u0438\u043e\u0442\u0435\u043a\u043e\u0439 GnuTLS («USE_GNUTLS=yes») \u0438 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[…]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":8,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[702],"tags":[],"class_list":["post-170699","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\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\t\t\n\t\t\n\n","aioseo_head_json":{"title":"\ud83e\udd47Zranite\u013enos\u0165 v Exim ved\u00faca k vzdialen\u00e9mu vykonaniu k\u00f3du na serveri | ProHoster","description":"V po\u0161tovom serveri Exim bola zisten\u00e1 kritick\u00e1 zranite\u013enos\u0165 (CVE-2026-45185), ktor\u00e1 umo\u017e\u0148uje vzdialen\u00e9 vykonanie k\u00f3du na 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ProHoster","og:description":"\u0412 \u043f\u043e\u0447\u0442\u043e\u0432\u043e\u043c \u0441\u0435\u0440\u0432\u0435\u0440\u0435 Exim \u0432\u044b\u044f\u0432\u043b\u0435\u043d\u0430 \u043a\u0440\u0438\u0442\u0438\u0447\u0435\u0441\u043a\u0430\u044f \u0443\u044f\u0437\u0432\u0438\u043c\u043e\u0441\u0442\u044c (CVE-2026-45185), \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0430\u044f \u0443\u0434\u0430\u043b\u0451\u043d\u043d\u043e \u0434\u043e\u0431\u0438\u0442\u044c\u0441\u044f \u0432\u044b\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u044f \u043a\u043e\u0434\u0430 \u043d\u0430 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