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Critical· 9.8official fix available

CVE-2026-63887

A critical vulnerability in the Linux kernel's iSCSI target implementation allows attackers to cause a heap buffer overflow by sending specially crafted login requests. The fix involves updating the kernel to a version that includes a bounds-checking patch.

publishedJul 19, 2026
last modifiedJul 27, 2026
sourcesNVD
severity · cvss
9.8
critical · how bad it is
exploitation · epss
<1%
51th percentile · chance of exploitation in 30 days
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →
auto-deletes from the system
counting…on Aug 19, 2026

An official fix is available, so this entry is kept for 30 days and then removed automatically.

01

Who is affected

Systems using the vulnerable Linux kernel version with iSCSI target functionality

02

Real-world impact

Could allow remote attackers to exploit the overflow to execute arbitrary code or crash the system.

03

Why this severity

CVSS 9.8 (Critical): High risk due to potential for remote code execution or denial of service.

04

What to do about it

official fix available
recommended steps
  1. 011. Check for available Linux kernel updates from your distribution.
  2. 022. Apply the kernel patch that includes the fix for CVE-2026-63887.
  3. 033. Reboot the system to ensure the updated kernel is loaded.

NVD description and CVE details

05

Timeline

  1. Jul 19, 2026 · 14d ago
    Published
    Disclosed and added to the National Vulnerability Database.
  2. Jul 20, 2026 · 13d ago
    Official fix available
    A vendor patch or mitigation now exists — see the remediation steps above.
  3. Jul 27, 2026 · 6d ago
    Advisory updated
    The NVD record was last revised.
06

How it’s attacked

Attack vectorNetwork (remote)
Attack complexityLow
Privileges requiredNone
User interactionNone needed
ScopeUnchanged
Confidentiality impactHigh
Integrity impactHigh
Availability impactHigh
07

References & advisories

NVD advisory ↗Search advisories ↗
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →
CVE-2026-63887: A critical vulnerability in the Linux kernel's iSCSI target implementa · Vulnary