Categories
CVE-2026-89948

Vulnerability in Linux kernel (CVE-2026-89948)

Summary

Vulnerability in Linux kernel (CVE-2026-89948). Risk of unauthorized operations or information disclosure.

Original description

The description as published by the source.

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

batman-adv: bla: fix freeing of claims on meshif deletion

When the mesh interface is getting deleted, then
batadv_bla_del_backbone_claims() (via batadv_bla_purge_backbone_gw()) could
make sure that all claims gets removed. But this function is only executed
when bat_priv->bla.claim_hash is not NULL. And since batadv_bla_free() is
always setting it to NULL before it is (indirectly) called, it was never
actually executed.

But the batadv_bla_purge_claims() -> batadv_handle_unclaim() is at the
moment too fragile because the BLA code is not handling the rehashing in
batadv_bla_update_orig_address(). The stored backbone address doesn't have
to be the one actually used for the hash bucket selection during the
initial adding of the backbone. The batadv_handle_unclaim() can therefore
fail to find the respective backbone for the unclaim and then stop the
deletion.

But the actual backbone_gw object is not needed for the unclaim because all
relevant information is always provided by the caller. And the check for
the existence of the backbone_gw doesn't provide any additional security
check for the deletion of a claim.

Source: NIST National Vulnerability Database 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-2026-89948 has been found in Linux kernel.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-89948" on the vendor's site.

CVE-2026-89948 (Linux kernel)
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 (unclassified) exists in Linux kernel.

📍 Affected scope

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

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 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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