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Technical advisory

USN-8815-1: libass vulnerabilities

Official source
EudorIA operational summary

What it means

Priority 70/100

Le vulnerabilità libass (CVE-2020-24994, CVE-2020-26682, CVE-2026-61627, CVE-2026-61626) permettono a un attaccante di causare un denial of service o eseguire codice arbitrario tramite file subtitle malformati. Le versioni colpite sono Ubuntu 14.04 LTS, 16.04 LTS, 18.04 LTS, 20.04 LTS, 24.04 LTS e 26.04 LTS. Le patch sono disponibili tramite Ubuntu Pro.

Why it matters

Le PMI italiane che utilizzano Ubuntu 14.04 LTS, 16.04 LTS, 18.04 LTS, 20.04 LTS, 24.04 LTS o 26.04 LTS potrebbero subire un denial of service o un esecuzione di codice arbitrario se non applicano le patch. Questo potrebbe compromettere la continuità operativa e la sicurezza dei sistemi.

Recommended actions

  1. Applicare le patch disponibili tramite Ubuntu Pro per le versioni colpite.
  2. Verificare le versioni di libass installate e applicare le patch necessarie.
  3. Monitorare i log di sistema e le applicazioni per segnali di crash o comportamenti anomali.
  4. Limitare l'accesso a file subtitle non verificati o provenienti da fonti non attendibili.
  5. Eseguire un aggiornamento completo del sistema per garantire la sicurezza.
  6. Valutare l'uso di Ubuntu Pro per ottenere una protezione a lungo termine.

Potential operational benefits

  • Riduzione della superficie esposta a vulnerabilità critiche.
  • Miglioramento della continuità operativa grazie alla mitigazione del denial of service.
  • Aumento della protezione contro attacchi di tipo exploit.
  • Sicurezza rafforzata grazie all'aggiornamento delle librerie.
Indications to confirm against the customer's technical and organisational perimeter.
Relevant controlsPatch managementFirewall NGFW / IPSMonitoraggio / SIEMSegmentazione di reteBackup & DR
AudienceITSOCCISO
Information centre

Translation in progress

Ubuntu Security

The official content is available in the original language. The Italian version will be published once automated checks are complete.

Text acquired from the source

It was discovered that libass incorrectly handled parsing operations for specific nested character strings. An attacker could use this issue to cause libass to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 14.04 LTS, Ubuntu 16.04 LTS, Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. (CVE-2020-24994) It was discovered that libass incorrectly handled certain outline processing operations. An attacker could use this issue to cause libass to crash, resulting in a denial of service. This issue only affected Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. (CVE-2020-26682) It was discovered that libass incorrectly handled certain ASS subtitle files when measuring wrapped lines. An attacker could use this issue to cause libass to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-61627) It was discovered that libass incorrectly handled certain Matroska subtitle chunks with negative ReadOrder values. An attacker could use this issue to cause libass to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-61626)

Source
Ubuntu Security Notices
Publishing entity
Ubuntu Security
Entity type
vendor security
Area
Global
Original language
en · translation in preparation
Publication
24/09/2026 16:57
MITRE ATT&CK
T1562, T1562.001
CVE
CVE-2020-24994, CVE-2020-26682, CVE-2026-61627, CVE-2026-61626
Technical scope

Affected products and versions

Verification in progress
Information not yet acquired.

The collector will check NVD and the available official vendor advisories.

Open the original source