CVE-2026-98255

CVE Details

Release Date:	2026-10-06
Impact:	Low	What is this?

Description

In the Linux kernel, the following vulnerability has been resolved: tcp: exclude old ACKs from tcp fast path Exclude old ACKs before SND.UNA from the tcp fast path as well as ACKs after SND.NXT. Such ACKs will fall through to the slow path, where tcp_ack() performs the appropriate validation and challenge ACK handling according to RFC5961 and Commit 3d501dd326fb1c7 ("tcp: do not accept ACK of bytes we never sent"). This prevents old ACKs from being accepted or modifying connection state as part of the fast path before appropriate ACK validation is applied. In particular, this prevents payload carried by a segment with an excessively old ACK from advancing RCV.NXT before the ACK is rejected.

See more information about CVE-2026-98255 from MITRE CVE dictionary and NIST NVD

NOTE: The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 metrics

Base Score:	0.0
Vector String:	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N
Version:	3.1
Attack Vector:	Network
Attack Complexity:	Low
Privileges Required:	None
User Interaction:	None
Scope:	Unchanged
Confidentiality Impact:	None
Integrity Impact:	None
Availability Impact:	None

Errata information

Platform	Errata	Release Date
Oracle Linux version 10 (kernel-uek)	ELSA-2026-500572	2026-11-02
Oracle Linux version 8 (kernel-uek)	ELSA-2026-500574	2026-11-02
Oracle Linux version 9 (kernel-uek)	ELSA-2026-500572	2026-11-02
Oracle Linux version 9 (kernel-uek)	ELSA-2026-500574	2026-11-02