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CVE Record

CVE-2026-31563: net: macb: Use dev_consume_skb_any() to free TX SKBs

In the Linux kernel, the following vulnerability has been resolved: net: macb: Use dev_consume_skb_any() to free TX SKBs The napi_consume_skb() function is not intended to be called in an IRQ disabled context. However, after commit 6bc8a5098bf4 ("net: macb: Fix tx_ptr_lock locking"), the freeing of TX SKBs is performed with IRQs disabled. To resolve the following call trace, use dev_consume_skb_any() for freeing TX SKBs: WARNING: kernel/softirq.c:430 at __local_bh_enable_ip+0x174/0x188, CPU#0: ksoftirqd/0/15 Modules linked in: CPU: 0 UID: 0 PID: 15 Comm: ksoftirqd/0 Not tainted 7.0.0-rc4-next-20260319-yocto-standard-dirty #37 PREEMPT Hardware name: ZynqMP ZCU102 Rev1.1 (DT) pstate: 200000c5 (nzCv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : __local_bh_enable_ip+0x174/0x188 lr : local_bh_enable+0x24/0x38 sp : ffff800082b3bb10 x29: ffff800082b3bb10 x28: ffff0008031f3c00 x27: 000000000011ede0 x26: ffff000800a7ff00 x25: ffff800083937ce8 x24: 0000000000017a80 x23: ffff000803243a78 x22: 0000000000000040 x21: 0000000000000000 x20: ffff000800394c80 x19: 0000000000000200 x18: 0000000000000001 x17: 0000000000000001 x16: ffff000803240000 x15: 0000000000000000 x14: ffffffffffffffff x13: 0000000000000028 x12: ffff000800395650 x11: ffff8000821d1528 x10: ffff800081c2bc08 x9 : ffff800081c1e258 x8 : 0000000100000301 x7 : ffff8000810426ec x6 : 0000000000000000 x5 : 0000000000000001 x4 : 0000000000000001 x3 : 0000000000000000 x2 : 0000000000000008 x1 : 0000000000000200 x0 : ffff8000810428dc Call trace: __local_bh_enable_ip+0x174/0x188 (P) local_bh_enable+0x24/0x38 skb_attempt_defer_free+0x190/0x1d8 napi_consume_skb+0x58/0x108 macb_tx_poll+0x1a4/0x558 __napi_poll+0x50/0x198 net_rx_action+0x1f4/0x3d8 handle_softirqs+0x16c/0x560 run_ksoftirqd+0x44/0x80 smpboot_thread_fn+0x1d8/0x338 kthread+0x120/0x150 ret_from_fork+0x10/0x20 irq event stamp: 29751 hardirqs last enabled at (29750): [<ffff8000813be184>] _raw_spin_unlock_irqrestore+0x44/0x88 hardirqs last disabled at (29751): [<ffff8000813bdf60>] _raw_spin_lock_irqsave+0x38/0x98 softirqs last enabled at (29150): [<ffff8000800f1aec>] handle_softirqs+0x504/0x560 softirqs last disabled at (29153): [<ffff8000800f2fec>] run_ksoftirqd+0x44/0x80

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A Linux macb Ethernet-driver flaw can mishandle transmitted network buffers while interrupts are disabled. The supplied CVSS score is 7.5, reflecting potentially serious service availability impact. Exposure appears limited to systems using the affected driver and kernel code; the source bundle does not establish data theft or modification.

Executive priority

High for availability-critical systems using macb; lower for systems without that driver. Establish exposure promptly, then apply vendor-supported fixes during an accelerated maintenance window. There is no supplied evidence of active exploitation or confidentiality impact.

Technical view

A locking change moved TX SKB release into an IRQ-disabled context, where napi_consume_skb() is unsuitable. The documented result is a kernel warning during macb_tx_poll(). Linux resolved the issue by using dev_consume_skb_any(). The evidence demonstrates an invalid execution context and availability risk, but does not establish a specific remote crash mechanism.

Likely exposure

Prioritize Linux hosts, appliances, and embedded systems that use the macb network driver and include the identified regression. The supplied version data mixes kernel releases and commit identifiers, so distribution-specific exposure cannot be determined reliably from this bundle alone.

Exploitation context

The supplied CVSS vector rates the issue network-reachable without privileges or user interaction. However, the bundle provides no exploit, proven remote trigger, or active-exploitation evidence, and KEV is false. Treat remote exploitability as unconfirmed rather than demonstrated.

Researcher notes

This is a regression associated with commit 6bc8a5098bf4. The fix replaces napi_consume_skb() with dev_consume_skb_any() for TX SKB release under IRQ-disabled locking. No CWE is supplied. The trace documents a context warning; further impact and reliable network triggering are not proven by the provided evidence.

Mitigation direction

  • Update to a vendor-supported kernel containing the applicable stable macb fix.
  • Confirm the corrected TX-buffer release change exists in custom or backported kernels.
  • Consult Linux distribution and device-vendor guidance for exact affected and fixed builds.
  • Prioritize exposed or availability-critical systems using the macb network driver.

Validation and detection

  • Inventory kernel versions and commit provenance on systems using macb networking.
  • Determine whether the macb driver is present and active on each system.
  • Compare vendor kernel builds against the referenced stable fixes.
  • Review kernel logs for the documented softirq warning and macb_tx_poll() call trace.
  • Retest network transmission under representative load after remediation.
Prepared
Confidence
high
Sources
8

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

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CVE-2026-31563 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
3Timeline events
1ADP providers
9Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Linux

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2026-31563Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

siemens-SADPADP container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxaeeafeb29b1b270302a9a85a13f7d70a68a3b9e6, 5430388a81113e62a2d48b5d7dc1e76231908ebf, 7db8aa3fc4ed0a2928246747b2514b0741a8187e, 6bc8a5098bf4a365c4086a4a4130bfab10a58260, 6bc8a5098bf4a365c4086a4a4130bfab10a58260, 6bc8a5098bf4a365c4086a4a4130bfab10a58260, a4cb0a15ab8e6d06c08229a2c7bdbe1f2454473f, 6.1.151, 6.6.105, 6.12.46, 6.16.6unaffected
LinuxLinux6.17, 0, 6.1.168, 6.6.131, 6.12.80, 6.18.21, 6.19.11, 7.0affected
Weakness

CWE details

No CWE listed

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