Description
In the Linux kernel, the following vulnerability has been resolved:

ipvs: fix reversed sequence option serialization

hton_seq() expects the host-order source first and the unaligned
network-order destination second. The version 1 sync sender passes these
arguments in reverse for both sequence blocks. This leaves 24 bytes of the
kmalloc-backed message unwritten. It may disclose stale heap data and
replace the live connection sequence state with values read from the
buffer.

Pass the connection sequence state as the source and the message payload as
the destination for both blocks.
Published: 2026-09-25
Score: n/a
EPSS: n/a
KEV: No
Impact: Information disclosure and disruption of IPVS session integrity
Action: Immediate patch
AI Analysis

Impact

A flaw exists in the Linux kernel’s IPVS implementation where the hton_seq() helper is called with its arguments reversed in the sync sender path. This mistake leaves portions of a heap‑allocated buffer unwritten, exposing stale data that can be read from the kernel. Because the same buffer is later copied back to live connection state, the replay of uninitialised bytes can overwrite legitimate sequence numbers and tamper with IPVS session management. As a result, the flaw can lead to inadvertent information disclosure of kernel memory and potential disruption of IPVS traffic handling.

Affected Systems

The vulnerability targets the Linux kernel, affecting all kernel versions of the Linux operating system that lack the commit fixing the reversed sequence option serialization in the ip_vs module. No specific version range is listed; thus any kernel prior to the patch may be vulnerable.

Risk and Exploitability

The CVSS score is not provided, but the flaw supplies a path that leverages uninitialised memory read to compromise IPVS session integrity. Exploitation requires the ability to trigger the sync sender path, which can be achieved through crafted IPVS synchronization packets sent to an IPVS setup. The likely attack vector is a remote crafted IPVS sync packet, and the likelihood of exploitation is uncertain due to lack of publicly known exploits, the absence of an EPSS score or KEV listing, and the need for network-level access to IPVS control interfaces. Nonetheless, the potential impact on data confidentiality and availability warrants prompt attention.

Generated by OpenCVE AI on September 25, 2026 at 16:14 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Apply the latest Linux kernel patch that includes the commit fixing the reversed sequence option serialization. Refer to the provided kernel repository links for the specific commits.
  • If a kernel update is infeasible, disable the IPVS sync_sender feature by setting "sync off" or limiting access to the IPVS control interface.
  • Ensure that any IPVS sync traffic originates only from trusted hosts and limit exposure to untrusted networks.

Generated by OpenCVE AI on September 25, 2026 at 16:14 UTC.

Tracking

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Advisories

No advisories yet.

History

Fri, 25 Sep 2026 16:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-119
CWE-200
CWE-788

Fri, 25 Sep 2026 10:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: ipvs: fix reversed sequence option serialization hton_seq() expects the host-order source first and the unaligned network-order destination second. The version 1 sync sender passes these arguments in reverse for both sequence blocks. This leaves 24 bytes of the kmalloc-backed message unwritten. It may disclose stale heap data and replace the live connection sequence state with values read from the buffer. Pass the connection sequence state as the source and the message payload as the destination for both blocks.
Title ipvs: fix reversed sequence option serialization
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-09-25T10:24:16.294Z

Reserved: 2026-09-25T10:19:56.074Z

Link: CVE-2026-98078

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-25T11:17:37.200

Modified: 2026-09-25T11:17:37.200

Link: CVE-2026-98078

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-25T16:15:16Z

Weaknesses
  • CWE-119

    Improper Restriction of Operations within the Bounds of a Memory Buffer

  • CWE-200

    Exposure of Sensitive Information to an Unauthorized Actor

  • CWE-788

    Access of Memory Location After End of Buffer