Improper Update of Reference Count Affecting kernel-debug-modules-internal package, versions *


Severity

Recommended
medium

Based on CentOS security rating.

Threat Intelligence

EPSS
0.18% (7th percentile)

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  • Snyk IDSNYK-CENTOS8-KERNELDEBUGMODULESINTERNAL-21506795
  • published23 Oct 2026
  • disclosed17 Sept 2026

Introduced: 17 Sep 2026

CVE-2026-93105  (opens in a new tab)
CWE-911  (opens in a new tab)

How to fix?

There is no fixed version for Centos:8 kernel-debug-modules-internal.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-debug-modules-internal package and not the kernel-debug-modules-internal package as distributed by Centos. See How to fix? for Centos:8 relevant fixed versions and status.

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

esp: do not unref managed frag pages in esp_ssg_unref()

esp_ssg_unref() releases the page references held on the source scatterlist after the AEAD operation completes. It calls skb_page_unref() on every frag page for an out-of-place transform (req->src != req->dst), and in the error path of esp_output_tail() (already_unref == true) on the request's own scatterlist.

This is wrong when the skb carries managed frags (SKBFL_MANAGED_FRAG_REFS). Managed frags are owned by a zerocopy ubuf and the skb does not hold a per-frag page reference; io_uring SEND_ZC with a registered buffer attaches the bvec pages this way via io_sg_from_iter(). The rest of the stack honours this invariant: skb_release_data() skips the per-frag unref when SKBFL_MANAGED_FRAG_REFS is set, and skb_zcopy_managed() is the guard used at the other unref sites.

esp_ssg_unref() is missing that guard, so for a managed-frag skb it drops a page reference the skb never acquired. This can underflow the page reference count and free a page that is still in use.

Guard the function with skb_zcopy_managed() so both unref paths are skipped for managed-frag skbs, matching skb_release_data().

CVSS Base Scores

version 3.1