--- cve: "CVE-2026-72421" severity: "CRITICAL" cvss: 10.0 epss: "56%" vendor: "Linux" kev: false exploited: false published: "2026-08-15 06:22:15" tags: [cve, security, critical] source: tsecurity.de CVE-Dossier exported: "2026-09-02T15:36:21+02:00" --- # CVE-2026-72421 > 10.0 CRITICAL ## Beschreibung In the Linux kernel, the following vulnerability has been resolved: ipv4: fib: Don't ignore error route in local/main tables. When CONFIG_IP_MULTIPLE_TABLES is enabled but no rule is added, fib_lookup() performs route lookup directly on two tables. Since the first lookup does not properly bail out, the result of an error route in the merged local/main table could be overwritten by another route in the default table: # unshare -n # ip link set lo up # ip route add 192.168.0.0/24 dev lo table 253 # ip route add unreachable 192.168.0.0/24 # ip route get 192.168.0.1 192.168.0.1 dev lo table default uid 0 cache Once a random rule is added, the error route is respected: # ip rule add table 0 # ip rule del table 0 # ip route get 192.168.0.1 RTNETLINK answers: No route to host Let's fix the inconsistent behaviour. ## CVSS-Vektor ``` CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N ``` | Metrik | Wert | Bewertung | |---|---|---| | AV Angriffsvektor | Netzwerk | bad | | AC Komplexität | Gering | bad | | PR Privilegien | Keine | bad | | UI Interaktion | Keine | bad | | S Scope | Verändert | bad | | C Vertraulichkeit | Hoch | bad | | I Integrität | Hoch | bad | | A Verfügbarkeit | Keine | good | ## Patch verfügbar (OSV) - Kernel ≥ 5.10.261 - Kernel ≥ 5.15.212 - Kernel ≥ 6.1.178 - Kernel ≥ 6.6.145 - Kernel ≥ 6.12.97 - Kernel ≥ 6.18.40 - Kernel ≥ 7.1.5 ## Referenzen - - - - - - - - --- _Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-72421) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_