--- cve: "CVE-2026-23455" severity: "CRITICAL" cvss: 9.1 epss: "1.3%" vendor: "Linux" kev: false exploited: false published: "2026-04-03 16:16:32" tags: [cve, security, critical] source: tsecurity.de CVE-Dossier exported: "2026-09-17T03:46:39+02:00" --- # CVE-2026-23455 > 9.1 CRITICAL ## Beschreibung In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_h323: check for zero length in DecodeQ931() In DecodeQ931(), the UserUserIE code path reads a 16-bit length from the packet, then decrements it by 1 to skip the protocol discriminator byte before passing it to DecodeH323_UserInformation(). If the encoded length is 0, the decrement wraps to -1, which is then passed as a large value to the decoder, leading to an out-of-bounds read. Add a check to ensure len is positive after the decrement. ## CVSS-Vektor ``` CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H ``` | Metrik | Wert | Bewertung | |---|---|---| | AV Angriffsvektor | Netzwerk | bad | | AC Komplexität | Gering | bad | | PR Privilegien | Keine | bad | | UI Interaktion | Keine | bad | | S Scope | Unverändert | good | | C Vertraulichkeit | Hoch | bad | | I Integrität | Keine | good | | A Verfügbarkeit | Hoch | bad | ## Patch verfügbar (OSV) - Kernel ≥ 5.10.253 - Kernel ≥ 5.15.203 - Kernel ≥ 6.1.167 - Kernel ≥ 6.6.130 - Kernel ≥ 6.12.78 - Kernel ≥ 6.18.20 - Kernel ≥ 6.19.10 ## Referenzen - - - - - - - - - - --- _Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-23455) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_