Categories
CVE-2026-31546 medium CVSS 5.5

Vulnerability in Linux kernel (CVE-2026-31546)

Summary

Vulnerability in Linux kernel (CVE-2026-31546). 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:

net: bonding: fix NULL deref in bond_debug_rlb_hash_show

rlb_clear_slave intentionally keeps RLB hash-table entries on
the rx_hashtbl_used_head list with slave set to NULL when no
replacement slave is available. However, bond_debug_rlb_hash_show
visites client_info->slave without checking if it's NULL.

Other used-list iterators in bond_alb.c already handle this NULL-slave
state safely:

  • rlb_update_client returns early on !client_info->slave
  • rlb_req_update_slave_clients, rlb_clear_slave, and rlb_rebalance
    compare slave values before visiting
  • lb_req_update_subnet_clients continues if slave is NULL

The following NULL deref crash can be trigger in
bond_debug_rlb_hash_show:

[ 1.289791] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 1.292058] RIP: 0010:bond_debug_rlb_hash_show (drivers/net/bonding/bond_debugfs.c:41)
[ 1.293101] RSP: 0018:ffffc900004a7d00 EFLAGS: 00010286
[ 1.293333] RAX: 0000000000000000 RBX: ffff888102b48200 RCX: ffff888102b48204
[ 1.293631] RDX: ffff888102b48200 RSI: ffffffff839daad5 RDI: ffff888102815078
[ 1.293924] RBP: ffff888102815078 R08: ffff888102b4820e R09: 0000000000000000
[ 1.294267] R10: 0000000000000000 R11: 0000000000000000 R12: ffff888100f929c0
[ 1.294564] R13: ffff888100f92a00 R14: 0000000000000001 R15: ffffc900004a7ed8
[ 1.294864] FS: 0000000001395380(0000) GS:ffff888196e75000(0000) knlGS:0000000000000000
[ 1.295239] CS:…

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-2026-31546 has been found in Linux kernel.
Risk of unauthorized operations or information disclosure. CVSS score: 5.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-31546" on the vendor's site.

CVE-2026-31546 (Linux kernel) — CWE-476 / CVSS v3 5.5
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-476) exists in Linux kernel.

📍 Affected scope

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

🔥 Severity

Severity: Medium (CVSS 5.5/10). 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。

Affected packages

Linux Kernel
[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.38"},{"fixed":"5.10.253"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.203"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.167"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.130"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.78"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.20"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.10"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

References

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