{"id":182826,"date":"2026-08-11T04:54:22","date_gmt":"2026-08-11T02:54:22","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/v-freenginx-i-nginx-dobavili-proverku-razmera-tekstovoj-peremennoj-pered-tem-kak-zapisyvat-v-neyo-dannye-cve"},"modified":"2026-08-11T04:54:22","modified_gmt":"2026-08-11T02:54:22","slug":"v-freenginx-i-nginx-dobavili-proverku-razmera-tekstovoj-peremennoj-pered-tem-kak-zapisyvat-v-neyo-dannye-cve","status":"publish","type":"post","link":"https:\/\/prohoster.info\/sk\/blog\/news\/v-freenginx-i-nginx-dobavili-proverku-razmera-tekstovoj-peremennoj-pered-tem-kak-zapisyvat-v-neyo-dannye-cve","title":{"rendered":"Do freenginx a nginx bola pridan\u00e1 kontrola ve\u013ekosti textovej premennej predt\u00fdm, ako sa do nej zap\u00ed\u0161u \u00fadaje (+ CVE)","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

<\/i><\/a>
3 <\/p>\n

TL;DR<\/b>: Po zisten\u00ed tretieho prep\u013a\u0148ania ved\u00facej pam\u00e4te (a pod\u013ea F5, RCE ak nie je ASLR) pri pr\u00e1ci s regul\u00e1rnymi v\u00fdrazmi a premenn\u00fdmi, sa v\u00fdvoj\u00e1r freenginx Maxim Dunin rozhodol, \u017ee je na\u010dase to zastavi\u0165, a pridal do svojho produktu kontrolu ve\u013ekosti premennej predt\u00fdm, ako do nej zap\u00ed\u0161e \u00fadaje. Odtia\u013eto si toto novinky vzal aj nginx, \u010do d\u00e1va n\u00e1dej na ukon\u010denie nov\u00fdch CVE na t\u00fato t\u00e9mu.<\/p>\n

Teraz podrobnosti.<\/p>\n

19. j\u00fana bola spraven\u00e1 zm\u011bnu<\/a> vo freenginx, ktor\u00e1 prid\u00e1va do popisu premennej pole end, ktor\u00e9 signalizuje koniec buffera. Predt\u00fdm tam bol len ukazovate\u013e na jeho za\u010diatok (pos), potrebn\u00e1 d\u013a\u017eka sa vypo\u010d\u00edtavala (a st\u00e1le vypo\u010d\u00edtava) vopred, a v \u010dase kop\u00edrovania \u00fadajov do premennej sa predpokladalo, \u017ee spr\u00e1vne vypo\u010d\u00edtan\u00e1 d\u013a\u017eka zaru\u010duje, \u017ee \u00fadaj sa zmest\u00ed do buffera. Bohu\u017eia\u013e, u\u017e dvakr\u00e1t v m\u00e1ji 2026 to z r\u00f4znych prehliadnut\u00ed tak nebolo (1 (linux.org.ru)<\/a>, 2 (linux.org.ru)<\/a>), \u010do viedlo k preplneniam buffera a zl\u00fdm n\u00e1sledkom. Tak\u017ee teraz pri vytv\u00e1ran\u00ed buffera premennej sa uklad\u00e1 aj ukazovate\u013e na jej koniec, a pred z\u00e1pisom do premennej \u00fadajov, ak sa \u00fadaje do nej nezmestia, spracovanie po\u017eiadavky bude kontrolovate\u013ene ukon\u010den\u00e9 s chybou. To znamen\u00e1, \u017ee chyby vo vypo\u010d\u00edtan\u00ed d\u013a\u017eky m\u00f4\u017eu aj na\u010falej existova\u0165, ale teraz sa nebud\u00fa \u0161\u00edri\u0165 po pam\u00e4ti, ale len zlyh\u00e1va\u0165 konkr\u00e9tnu http-\u017eiados\u0165. Nasleduj\u00facimi commitmi (2 (freenginx.org)<\/a>, 3 (freenginx.org)<\/a>) bola pridan\u00e1 podobn\u00e1 ochrana do in\u00fdch \u010dast\u00ed k\u00f3du, vr\u00e1tane k\u00f3du pre vedenie pr\u00edstupov\u00e9ho logu. 7. j\u00fala bola zverejnen\u00e1 verzia freenginx 1.31.3<\/a>, ktor\u00e1 obsahuje toto opravenie.<\/p>\n

<\/p>\n

15. j\u00fala boli tieto commity prevzat\u00e9 nginx-om (1 (github.com)<\/a>, 2 (github.com)<\/a>, 3 (github.com)<\/a>, nejak\u00fdm sp\u00f4sobom zamie\u0148aj\u00fac druh\u00fd a tret\u00ed v re\u0165azci), probl\u00e9mu bola pridelen\u00e1 CVE-2026-42533<\/a>, a F5 vydalo ofici\u00e1lne SA (f5.com)<\/a>.<\/p>\n

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

Pokia\u013e ide o konkr\u00e9tnu zranite\u013enos\u0165 tentokr\u00e1t: prejavuje sa pri pou\u017e\u00edvan\u00ed direkt\u00edvy map s regul\u00e1rnymi v\u00fdrazmi a vy\u010dlenen\u00fdmi parametrami. \u010co sa t\u00fdka ostatn\u00fdch podmienok potrebn\u00fdch na jej aktiv\u00e1ciu, text v popise commitu a text v SA sa trochu l\u00ed\u0161ia: v SA je uveden\u00e9, \u017ee v bud\u00facnosti by malo by\u0165 vypo\u010d\u00edtan\u00e9 ak\u00e9si re\u0165azec, ktor\u00fd vyu\u017e\u00edva vy\u010dlenen\u00fd parameter z map, sk\u00f4r ako v\u00fdsledok toho ist\u00e9ho mapu. V popise commitu je v pr\u00edklade medzi t\u00fdmito krokmi zahrnut\u00e9 aj nulovanie premennej, ktor\u00e1 obsahuje vy\u010dlenen\u00fd parameter. Ako tak, v v\u00e4\u010d\u0161ine nasaden\u00fdch nginx-ov sa podobn\u00e9 pravdepodobne nestretne, a zranite\u013enos\u0165 takto malo koho zasiahla. Takisto je potrebn\u00e9 poznamena\u0165, \u017ee opravy v\u00fdpo\u010dtu d\u013a\u017eky konkr\u00e9tne v tomto pr\u00edpade v zakommitovan\u00fdch \u00faprav\u00e1ch sa zdaj\u00fa ch\u00fdba\u0165 (alebo som h\u013eadal zle?), existuje iba ochrana, ktor\u00e1 tento probl\u00e9m premen\u00ed na kontrolovan\u00e9 zlyhanie HTTP po\u017eiadavky. Hoci 19. j\u00fala sa do freenginx pridali ak\u00e9si opravy (5bfb<\/a>, 7622<\/a>, b906<\/a>) v\u00fdpo\u010dtu d\u013a\u017eky pre podobn\u00fa situ\u00e1ciu, ale presne na prv\u00fd poh\u013ead to nie je jasn\u00e9, \u010di to tak je alebo nie. <\/p>\n

Zranite\u013enos\u0165 sa objavila vo verzii nginx 0.9.6, opravy sa dostali do verzi\u00ed freenginx 1.31.3, nginx 1.30.4, nginx 1.31.3.<\/p>\n

V SA nginx s\u00fa uveden\u00e9 po\u010fakovania niektor\u00fdm osob\u00e1m za nez\u00e1visl\u00e9 spr\u00e1vy o zranite\u013enosti a dodr\u017eiavanie \u201e\u0161tandardov koordinovan\u00e9ho zverej\u0148ovania inform\u00e1ci\u00ed\u201c:<\/p>\n

<\/p>\n

F5 uzn\u00e1va Minga Xuana, DKD (@pidifn), Ji\u2019an Zhoua a Zhen Yana z AntAISecurityLab, Rafaela Gaceka, Sergiia Negodiuka z EVO.company, Lama Jun Ronga z Calif.io, Mufeeda VH z Winfunc Research (winfunc.com), Vexera AI (https:\/\/vexera.ai<\/a>), Tu Tran Dinh (@1w4y), Stan Shaw (cyberstan), qianshuidewajueji, zenneth (randomguy6407), Zhenpeng (Leo) Lin z depthfirst, Lukasa Johannesa Moellera, Melih Tolga Sahina z Vodafone T\u00fcrkiye, Ayoub Nabil Boubagrat (GitHub: @ayoubnabil) a Milana Jovica (Kljunowsky) za to, \u017ee na t\u00fato problematiku nez\u00e1visle upozornili a dodr\u017eiavali najvy\u0161\u0161ie \u0161tandardy koordinovan\u00e9ho zverejnenia.<\/p>\n

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

Vo freenginx sprievodn\u00e9 inform\u00e1cie o oprave sa v podstate obmedzuj\u00fa na spr\u00e1vu pri commite. V changelog<\/a>-toto opravenie nie je ozna\u010den\u00e9 ani podpisom \u201ebezpe\u010dnos\u0165\u201c (security), ani \u201eoprava\u201c (bugfix), iba \u201epr\u00eddavok\u201c (feature). Je pravdepodobn\u00e9, \u017ee autor pova\u017eoval tento probl\u00e9m za nekritick\u00fd. Ako s\u00favisia spr\u00e1vy o probl\u00e9me zo strany uveden\u00fdch os\u00f4b v F5 a komit prevzat\u00fd z freenginx, \u010di informovali (alebo niekto in\u00fd) autora freenginx o probl\u00e9me, sa zisti\u0165 nepodarilo. <\/p>\n

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

3 TL;DR: \u0421\u0442\u043e\u043b\u043a\u043d\u0443\u0432\u0448\u0438\u0441\u044c \u0441 \u0442\u0440\u0435\u0442\u044c\u0438\u043c \u043e\u0431\u043d\u0430\u0440\u0443\u0436\u0435\u043d\u043d\u044b\u043c \u0437\u0430 2026 \u0433\u043e\u0434 \u043f\u0435\u0440\u0435\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u0435\u043c \u0431\u0443\u0444\u0435\u0440\u0430 (\u0438, \u043f\u043e \u0432\u0435\u0440\u0441\u0438\u0438 F5, RCE \u0435\u0441\u043b\u0438 \u043d\u0435\u0442 ASLR) \u043f\u0440\u0438 \u0440\u0430\u0431\u043e\u0442\u0435 \u0441 \u0440\u0435\u0433\u044d\u043a\u0441\u043f\u0430\u043c\u0438 \u0438 \u043f\u0435\u0440\u0435\u043c\u0435\u043d\u043d\u044b\u043c\u0438, \u0440\u0430\u0437\u0440\u0430\u0431\u043e\u0442\u0447\u0438\u043a freenginx \u041c\u0430\u043a\u0441\u0438\u043c \u0414\u0443\u043d\u0438\u043d \u0440\u0435\u0448\u0438\u043b, \u0447\u0442\u043e \u043f\u043e\u0440\u0430 \u044d\u0442\u043e \u043f\u0440\u0435\u043a\u0440\u0430\u0449\u0430\u0442\u044c, \u0438 \u0434\u043e\u0431\u0430\u0432\u0438\u043b \u0432 \u0441\u0432\u043e\u0439 \u043f\u0440\u043e\u0434\u0443\u043a\u0442 \u043f\u0440\u043e\u0432\u0435\u0440\u043a\u0443 \u0440\u0430\u0437\u043c\u0435\u0440\u0430 \u043f\u0435\u0440\u0435\u043c\u0435\u043d\u043d\u043e\u0439 \u043f\u0435\u0440\u0435\u0434 \u0442\u0435\u043c \u043a\u0430\u043a \u0437\u0430\u043f\u0438\u0441\u044b\u0432\u0430\u0442\u044c \u0432 \u043d\u0435\u0451 \u0434\u0430\u043d\u043d\u044b\u0435. \u041e\u0442\u0442\u0443\u0434\u0430 \u044d\u0442\u043e \u043d\u043e\u0432\u043e\u0432\u0432\u0435\u0434\u0435\u043d\u0438\u0435 \u0443\u0442\u0430\u0449\u0438\u043b\u0438 \u043a \u0441\u0435\u0431\u0435 […]<\/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-182826","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\n","aioseo_head_json":{"title":"\ud83e\udd47Do freenginx a nginx pridali kontrolu ve\u013ekosti textovej premennej predt\u00fdm, ne\u017e do nej zap\u00ed\u0161u \u00fadaje (+ CVE) | ProHoster","description":"3 TL;DR: Narazili sme na tretie zisten\u00e9 prete\u010denie vyrovn\u00e1vacej pam\u00e4te (a pod\u013ea verzie 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F5.","og:url":"https:\/\/prohoster.info\/sk\/blog\/news\/v-freenginx-i-nginx-dobavili-proverku-razmera-tekstovoj-peremennoj-pered-tem-kak-zapisyvat-v-neyo-dannye-cve","og:image":"https:\/\/prohoster.info\/wp-content\/uploads\/2021\/11\/logo-350.jpg","og:image:secure_url":"https:\/\/prohoster.info\/wp-content\/uploads\/2021\/11\/logo-350.jpg","og:image:width":350,"og:image:height":350,"article:published_time":"2026-08-11T02:54:22+00:00","article:modified_time":"2026-08-11T02:54:22+00:00","article:publisher":"https:\/\/www.facebook.com\/prohoster"},"aioseo_meta_data":{"post_id":"182826","title":null,"description":null,"keywords":null,"keyphrases":{"focus":[],"additional":[]},"primary_term":null,"canonical_url":null,"og_title":null,"og_description":null,"og_object_type":"default","og_image_type":"default","og_image_url":null,"og_image_width":null,"og_image_height":null,"og_image_custom_url":null,"og_image_custom_fields":null,"og_video":null,"og_custom_url":null,"og_article_section":null,"og_article_tags":null,"twitter_use_og":false,"twitter_card":"default","twitter_image_type":"default","twitter_image_url":null,"twitter_image_custom_url":null,"twitter_image_custom_fields":null,"twitter_title":null,"twitter_description":null,"schema":{"blockGraphs":[],"customGraphs":[],"default":{"data":{"Article":[],"Course":[],"Dataset":[],"FAQPage":[],"Movie":[],"Person":[],"Product":[],"ProductReview":[],"Car":[],"Recipe":[],"Service":[],"SoftwareApplication":[],"WebPage":[]},"graphName":"","isEnabled":true},"graphs":[]},"schema_type":"default","schema_type_options":null,"pillar_content":false,"robots_default":true,"robots_noindex":false,"robots_noarchive":false,"robots_nosnippet":false,"robots_nofollow":false,"robots_noimageindex":false,"robots_noodp":false,"robots_notranslate":false,"robots_max_snippet":null,"robots_max_videopreview":null,"robots_max_imagepreview":"large","priority":null,"frequency":null,"local_seo":null,"seo_analyzer_scan_date":null,"breadcrumb_settings":null,"limit_modified_date":false,"reviewed_by":null,"ai":null,"created":"2026-08-11 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