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CVE-2026-52923 high CVSS 7.8

Vulnerability in Linux kernel (CVE-2026-52923)

Summary

Vulnerability in Linux kernel (CVE-2026-52923). Successful exploitation can lead to full system takeover.

Original description

The description as published by the source.

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

ipc: limit next_id allocation to the valid ID range

The checkpoint/restore sysctl path can request the next SysV IPC id
through ids->next_id. ipc_idr_alloc() currently forwards that request to
idr_alloc() with an open-ended upper bound.

If the valid tail of the SysV IPC id space is full, the allocation can
spill beyond ipc_mni. The returned SysV IPC id still uses the normal
index encoding, so later lookup and removal can target the wrong slot.
This leaves the real IDR entry behind and breaks the IDR state for the
object.

The bug is in ipc_idr_alloc() in the checkpoint/restore path.

  1. ids->next_id is passed to:

    idr_alloc(&ids->ipcs_idr, new, ipcid_to_idx(next_id), 0, ...)

  2. The zero upper bound makes the allocation effectively open-ended.
    Once the valid SysV IPC tail is occupied, idr_alloc() can spill past
    ipc_mni and allocate an entry beyond the valid IPC id range.

  3. The new object id is still encoded with the narrower SysV IPC index
    width:

    new->id = (new->seq << ipcmni_seq_shift()) + idx

  4. Later removal goes through ipc_rmid(), which uses:

    ipcid_to_idx(ipcp->id)

    That truncates the real IDR index. An object actually stored at a
    high index can then be removed as if it lived at a low in-range
    index.

  5. For shared memory, shm_destroy() frees the current object anyway, but
    the real high IDR slot is left behind as a dangling pointer.

  6. A subsequent wa…

Source: GitHub Security Advisories (Global) NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-52923 has been found in Linux kernel.
Successful exploitation can lead to full system takeover. CVSS score: 7.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-52923" on the vendor's site.

CVE-2026-52923 (Linux kernel) — CWE-401 / CVSS v3 7.8
Attack vector: local / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-401) exists in Linux kernel.

📍 Affected scope

Check the vendor advisory for the affected versions of Linux kernel.

🔥 Severity

Severity: High (CVSS 7.8/10). Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    Audit SBOM/dependencies for affected components.

    資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。

  2. 2
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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