Heap-based buffer overflow in Linux kernel - CVE-2026-63887
Published: July 20, 2026
Vulnerability identifier: #VU138771
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-63887
CWE-ID: CWE-122
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to a heap-based buffer overflow in iscsi_encode_text_output() when processing iSCSI login text parameters. A remote attacker can send a specially crafted login request with many minimal key-value pairs to cause a denial of service.
The issue can be triggered by expansion of unknown keys into larger "NotUnderstood" response records during login negotiation.
How to mitigate CVE-2026-63887
Install security update from vendor's repository.
Sources
- https://git.kernel.org/stable/c/26e4a304b7e6f1338c675d527608d32549c091db
- https://git.kernel.org/stable/c/30bf335e8fe170322080ee001f05ca29c50680b3
- https://git.kernel.org/stable/c/4e9f0c4a645c995bc75c06c7b3644254ffb4c76b
- https://git.kernel.org/stable/c/594a40360012ce5f94c715d5e3b20fa3af7d525a
- https://git.kernel.org/stable/c/b19382dfc6e7dee6d3859ba44b6ca29e97a51627
- https://git.kernel.org/stable/c/bf33e01f88388c43e285492a63e539df6ffed64c
- https://git.kernel.org/stable/c/cb84e974fb172bc71386289f37b78ea679410b39
- https://git.kernel.org/stable/c/efe633e600a0ac68357206fede21b1ac8178f3b8