{"id":15822,"date":"2026-10-30T17:32:35","date_gmt":"2026-10-30T14:32:35","guid":{"rendered":"https:\/\/www.inetmar.com\/blog\/?p=15822"},"modified":"2026-10-30T17:32:35","modified_gmt":"2026-10-30T14:32:35","slug":"ubuntu-sunucularda-kritik-acik","status":"publish","type":"post","link":"https:\/\/www.inetmar.com\/blog\/ubuntu-sunucularda-kritik-acik\/","title":{"rendered":"Ubuntu Sunucular\u0131nda Kritik Linux A\u00e7\u0131\u011f\u0131: CVE-2026-98432 Uzaktan Sald\u0131r\u0131 Riski Olu\u015fturuyor"},"content":{"rendered":"

Ubuntu taraf\u0131ndan yay\u0131mlanan CVE-2026-98432 numaral\u0131 g\u00fcvenlik duyurusu, Linux \u00e7ekirde\u011finin a\u011f ileti\u015fimiyle ilgili bir b\u00f6l\u00fcm\u00fcnde ciddi bir bellek y\u00f6netimi hatas\u0131na i\u015faret ediyor. Canonical, 15 Ekim 2026’da yay\u0131mlad\u0131\u011f\u0131 ve 29 Ekim’de g\u00fcncelledi\u011fi duyuruda a\u00e7\u0131\u011f\u0131 High \u00f6ncelik seviyesinde<\/strong>, CVSS 3 de\u011ferlendirmesinde ise 9.8 Critical<\/strong> olarak s\u0131n\u0131fland\u0131rd\u0131.<\/p>\n

A\u00e7\u0131k, TCP ba\u011flant\u0131lar\u0131n\u0131n i\u015flenmesi s\u0131ras\u0131nda ortaya \u00e7\u0131kabilen bir use-after-free<\/em> (serbest b\u0131rak\u0131lm\u0131\u015f belle\u011fin yeniden kullan\u0131lmas\u0131) hatas\u0131ndan kaynaklan\u0131yor. Belirli ko\u015fullarda tetiklenebilen bu hata, \u00e7ekirdek seviyesinde g\u00fcvenlik riski olu\u015fturuyor. Ubuntu sunucular\u0131n\u0131 y\u00f6neten sistem y\u00f6neticilerinin, kulland\u0131klar\u0131 \u00e7ekirdek paketlerinin durumunu kontrol etmesi gerekiyor.<\/p>\n

CVE-2026-98432 g\u00fcvenlik a\u00e7\u0131\u011f\u0131 nas\u0131l ortaya \u00e7\u0131k\u0131yor?<\/h2>\n

Canonical’\u0131n a\u00e7\u0131klamas\u0131na g\u00f6re sorun, Linux \u00e7ekirde\u011finde IPv4 TCP ba\u011flant\u0131 isteklerinin i\u015flenmesi s\u0131ras\u0131nda ya\u015fanan e\u015fzamanl\u0131 i\u015flem \u00e7ak\u0131\u015fmas\u0131ndan kaynaklan\u0131yor.<\/p>\n

tcp_v4_syn_recv_sock()<\/code> fonksiyonu, ba\u011flant\u0131 iste\u011fine ait baz\u0131 se\u00e7eneklerin sahipli\u011fini yeni olu\u015fturulan ba\u011flant\u0131 soketine aktar\u0131yor. Ancak ayn\u0131 ba\u011flant\u0131 iste\u011fi \u00fczerinde ba\u015fka bir i\u015flem e\u015fzamanl\u0131 olarak \u00e7al\u0131\u015ft\u0131\u011f\u0131nda, ilgili bellek alan\u0131 hen\u00fcz kullan\u0131lmaya devam ederken serbest b\u0131rak\u0131labiliyor.<\/p>\n

Bu durum, \u00e7ekirde\u011fin art\u0131k ge\u00e7erli olmayan bir bellek alan\u0131na eri\u015fmesine neden oluyor. Teknik olarak use-after-free olarak adland\u0131r\u0131lan bu hata, bellek g\u00fcvenli\u011fi a\u00e7\u0131s\u0131ndan \u00f6nemli bir zafiyet olu\u015fturuyor.<\/p>\n

Ubuntu duyurusunda benzer bir problemin ba\u011flant\u0131 iste\u011finin ba\u015fka bir sokete ta\u015f\u0131nmas\u0131 s\u0131ras\u0131nda da ortaya \u00e7\u0131kabildi\u011fi belirtiliyor. Bu senaryoda eski ba\u011flant\u0131 iste\u011fi ile kopyalanan yeni istek ayn\u0131 bellek alan\u0131n\u0131 payla\u015fabiliyor. \u0130\u015flemler farkl\u0131 CPU \u00e7ekirdeklerinde e\u015fzamanl\u0131 y\u00fcr\u00fct\u00fcld\u00fc\u011f\u00fcnde, bellek alan\u0131 h\u00e2l\u00e2 kullan\u0131l\u0131rken serbest b\u0131rak\u0131labiliyor.<\/p>\n

Sorunun giderilmesi i\u00e7in ilgili bellek alanlar\u0131n\u0131n hemen serbest b\u0131rak\u0131lmas\u0131 yerine RCU bekleme s\u00fcresinin ard\u0131ndan temizlenmesini sa\u011flayan kfree_rcu()<\/code> y\u00f6nteminin kullan\u0131lmas\u0131 gerekiyor.<\/p>\n

Hangi Ubuntu s\u00fcr\u00fcmleri etkileniyor?<\/h2>\n

Canonical’\u0131n g\u00fcvenlik duyurusunda farkl\u0131 Ubuntu s\u00fcr\u00fcmleri ve \u00e7ekirdek paketleri i\u00e7in ayr\u0131 ayr\u0131 durum bilgileri yay\u0131mland\u0131. Ana linux<\/code> paketi kapsam\u0131nda a\u00e7\u0131klanan durum \u015f\u00f6yle:<\/p>\n\n\n\n\n\n\n\n\n\n\n\n
Ubuntu s\u00fcr\u00fcm\u00fc<\/th>\nDuyurudaki durum<\/th>\n<\/tr>\n
Ubuntu 26.10<\/td>\nD\u00fczeltme \u00fczerinde \u00e7al\u0131\u015f\u0131l\u0131yor<\/td>\n<\/tr>\n
Ubuntu 26.04 LTS<\/td>\nD\u00fczeltme \u00fczerinde \u00e7al\u0131\u015f\u0131l\u0131yor<\/td>\n<\/tr>\n
Ubuntu 24.04 LTS<\/td>\nD\u00fczeltme \u00fczerinde \u00e7al\u0131\u015f\u0131l\u0131yor<\/td>\n<\/tr>\n
Ubuntu 22.04 LTS<\/td>\nD\u00fczeltme \u00fczerinde \u00e7al\u0131\u015f\u0131l\u0131yor<\/td>\n<\/tr>\n
Ubuntu 20.04 LTS<\/td>\nEtkileniyor<\/td>\n<\/tr>\n
Ubuntu 18.04 LTS<\/td>\nEtkileniyor<\/td>\n<\/tr>\n
Ubuntu 16.04 LTS<\/td>\nEtkileniyor<\/td>\n<\/tr>\n
Ubuntu 14.04 LTS<\/td>\nEtkilenmiyor<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Burada \u00f6nemli bir ayr\u0131nt\u0131 bulunuyor: Ubuntu’nun duyurusunda yaln\u0131zca standart linux<\/code> paketi de\u011fil, HWE ve bulut ortamlar\u0131nda kullan\u0131lan AWS, Azure, GCP gibi farkl\u0131 \u00e7ekirdek paketleri de listeleniyor. Bu paketlerin g\u00fcvenlik durumu, kullan\u0131lan \u00e7ekirdek varyant\u0131na ve Ubuntu s\u00fcr\u00fcm\u00fcne g\u00f6re de\u011fi\u015febiliyor.<\/p>\n

Dolay\u0131s\u0131yla yaln\u0131zca Ubuntu s\u00fcr\u00fcm numaras\u0131na bakarak sunucunun etkilenip etkilenmedi\u011fine karar vermek yeterli de\u011fil. Sunucuda kullan\u0131lan \u00e7ekirdek paketinin de Canonical’\u0131n ilgili g\u00fcvenlik duyurusundaki durumuyla kar\u015f\u0131la\u015ft\u0131r\u0131lmas\u0131 gerekiyor.<\/p>\n

Ubuntu sunucular\u0131nda ne yap\u0131lmal\u0131?<\/h2>\n

29 Ekim 2026 tarihli duyuruda Ubuntu 26.10, 26.04 LTS, 24.04 LTS ve 22.04 LTS i\u00e7in baz\u0131 \u00e7ekirdek paketlerinde d\u00fczeltme \u00e7al\u0131\u015fmalar\u0131n\u0131n devam etti\u011fi belirtiliyor. Bu nedenle g\u00fcncellemenin t\u00fcm sistemlere yay\u0131mland\u0131\u011f\u0131n\u0131 varsaymamak gerekiyor.<\/p>\n

Ubuntu sunucularda mevcut paketleri kontrol etmek i\u00e7in \u015fu komut kullan\u0131labilir:<\/p>\n

sudo apt update\r\nsudo apt list --upgradable<\/code><\/pre>\n
Kurulu \u00e7ekirdek s\u00fcr\u00fcm\u00fcn\u00fc g\u00f6rmek i\u00e7in:<\/p>\n
uname -r<\/code><\/pre>\n
G\u00fcncellemeler yay\u0131mland\u0131\u011f\u0131nda sistem paketlerini g\u00fcncellemek i\u00e7in:<\/p>\n
sudo apt upgrade<\/code><\/pre>\n
\u00c7ekirdek g\u00fcncellemesinin kurulmas\u0131n\u0131n ard\u0131ndan yeni \u00e7ekirde\u011fin devreye girmesi i\u00e7in sunucunun yeniden ba\u015flat\u0131lmas\u0131 gerekebilir:<\/p>\n
sudo reboot<\/code><\/pre>\n
\u00dcretim ortam\u0131nda \u00e7al\u0131\u015fan VPS ve VDS sunucular\u0131nda yeniden ba\u015flatma i\u015flemi \u00f6ncesinde bak\u0131m plan\u0131 yap\u0131lmas\u0131, \u00e7al\u0131\u015fan servislerin ve uygulamalar\u0131n kontrol edilmesi \u00f6nem ta\u015f\u0131yor. Ayr\u0131ca g\u00fcncelleme sonras\u0131nda sistemin beklenen \u00e7ekirdek s\u00fcr\u00fcm\u00fcyle a\u00e7\u0131ld\u0131\u011f\u0131 do\u011frulanmal\u0131.<\/p>\n
Sunucu y\u00f6neticileri g\u00fcvenlik duyurusunu takip etmeli<\/h2>\n
CVE-2026-98432, Ubuntu Linux \u00e7ekirde\u011finin TCP\/IP ba\u011flant\u0131 y\u00f6netimiyle ilgili bir bellek hatas\u0131ndan kaynaklan\u0131yor. Canonical’\u0131n yay\u0131mlad\u0131\u011f\u0131 duyuru, a\u00e7\u0131\u011f\u0131n farkl\u0131 \u00e7ekirdek paketleri \u00fczerindeki durumunu ayr\u0131 ayr\u0131 g\u00f6steriyor. Bu nedenle \u00f6zellikle birden fazla Ubuntu s\u00fcr\u00fcm\u00fc veya farkl\u0131 \u00e7ekirdek varyantlar\u0131 kullanan sunucu altyap\u0131lar\u0131nda paket bazl\u0131 kontrol yap\u0131lmas\u0131 gerekiyor.<\/p>\n
Sistem y\u00f6neticilerinin Canonical taraf\u0131ndan yay\u0131mlanan g\u00fcvenlik duyurusunu takip etmesi, ilgili \u00e7ekirdek g\u00fcncellemelerini geciktirmemesi ve g\u00fcncelleme sonras\u0131nda sunucular\u0131n yeniden ba\u015flatma gereksinimini kontrol etmesi \u00f6neriliyor.<\/p>\n
Resm\u00ee kaynak:<\/strong> Canonical Ubuntu \u2013 CVE-2026-98432<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
Ubuntu taraf\u0131ndan yay\u0131mlanan CVE-2026-98432 numaral\u0131 g\u00fcvenlik duyurusu, Linux \u00e7ekirde\u011finin a\u011f ileti\u015fimiyle ilgili bir b\u00f6l\u00fcm\u00fcnde ciddi bir bellek y\u00f6netimi hatas\u0131na i\u015faret ediyor. Canonical, 15 Ekim 2026’da yay\u0131mlad\u0131\u011f\u0131 ve 29 Ekim’de g\u00fcncelledi\u011fi duyuruda a\u00e7\u0131\u011f\u0131 High \u00f6ncelik seviyesinde,...<\/p>\n","protected":false},"author":6,"featured_media":15823,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[24],"tags":[1741,1729,1740],"class_list":["post-15822","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-genel","tag-cve-2026-98432","tag-guvenlik-acigi","tag-ubuntu"],"_links":{"self":[{"href":"https:\/\/www.inetmar.com\/blog\/wp-json\/wp\/v2\/posts\/15822","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.inetmar.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.inetmar.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.inetmar.com\/blog\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/www.inetmar.com\/blog\/wp-json\/wp\/v2\/comments?post=15822"}],"version-history":[{"count":1,"href":"https:\/\/www.inetmar.com\/blog\/wp-json\/wp\/v2\/posts\/15822\/revisions"}],"predecessor-version":[{"id":15824,"href":"https:\/\/www.inetmar.com\/blog\/wp-json\/wp\/v2\/posts\/15822\/revisions\/15824"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.inetmar.com\/blog\/wp-json\/wp\/v2\/media\/15823"}],"wp:attachment":[{"href":"https:\/\/www.inetmar.com\/blog\/wp-json\/wp\/v2\/media?parent=15822"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.inetmar.com\/blog\/wp-json\/wp\/v2\/categories?post=15822"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.inetmar.com\/blog\/wp-json\/wp\/v2\/tags?post=15822"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}