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

net: spacemit: clear TX descriptor on fragment mapping failure

emac_tx_mem_map() writes TX_DESC_0_OWN into the ring descriptor for
every slot beyond old_head as soon as that slot's memset()'d local
copy is committed with "*tx_desc_addr = tx_desc", i.e. before the
buffers for that slot have necessarily all been mapped successfully.
If emac_tx_map_frag() then fails on a later fragment, the err_free_skb
path calls emac_free_tx_buf() to unmap and drop the skb, but leaves
the already-written descriptor memory untouched, and tx_ring->head is
never advanced past old_head (the "tx_ring->head = head" store is
skipped by the goto).

So a slot between old_head and the rolled-back head can be left with
TX_DESC_0_OWN set and buffer_addr_{1,2} pointing at DMA mappings that
emac_free_tx_buf() just tore down, while software considers that slot
free again. The next successful emac_tx_mem_map() call only rebuilds
old_head itself; if the DMA engine auto-advances into the following
descriptor once it finishes old_head's packet, it will fetch that
stale, already-unmapped address.

emac_tx_clean_desc() already treats emac_free_tx_buf() and clearing
the descriptor as a pair when reclaiming completed descriptors; do
the same in the mapping failure path.
Published: 2026-10-18
Score: 4.7 Medium
EPSS: < 1% Very Low
KEV: No
Impact: Memory Corruption
Action: Apply Patch
AI Analysis

Impact

The flaw lies in the spacemit network driver, where a failure in mapping a transmitted fragment leaves a transmit descriptor with a stale DMA address that has already been unmapped. Software incorrectly marks the slot as free, yet the underlying DMA engine may still attempt to use the stale descriptor, leading to kernel memory corruption or a system crash. Such corruption could affect integrity and availability of the system. It is inferred that an attacker could trigger this failure by sending malformed fragmented traffic to the driver from a remote host or accessing the interface locally, but this is not explicitly confirmed in the source data.

Affected Systems

All Linux kernel builds that include the spacemit driver are affected. The data do not provide specific version ranges or vendor patch levels, so any kernel with the driver is potentially vulnerable.

Risk and Exploitability

The vulnerability is a moderate‑severity kernel memory corruption flaw with a CVSS score of 4.7. The EPSS score is less than 1%, indicating a low probability of exploitation, and it is not listed in the CISA KEV catalog. It is inferred that the flaw could be triggered by sending malformed fragmented traffic to the driver from a remote host or accessing the interface locally. The stale DMA address may cause the DMA engine to fetch invalid memory, potentially leading to a crash or data corruption. The overall risk primarily impacts availability and integrity rather than enabling remote code execution.

Generated by OpenCVE AI on October 20, 2026 at 21:19 UTC.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Apply the latest Linux kernel update that includes the spacemit driver patch.
  • If an immediate kernel update is not possible, unload or disable the spacemit driver to prevent the vulnerable code from executing.
  • Limit network traffic that could trigger large or fragmented packet handling, for example by configuring firewall rules or rate limiting, to reduce the chances of exploitation.

Generated by OpenCVE AI on October 20, 2026 at 21:19 UTC.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

History

Tue, 20 Oct 2026 19:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-416

Tue, 20 Oct 2026 12:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-825
References
Metrics threat_severity

None

 cvssV3_1

{'score': 4.7, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Sun, 18 Oct 2026 18:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-416

Sun, 18 Oct 2026 15:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: net: spacemit: clear TX descriptor on fragment mapping failure emac_tx_mem_map() writes TX_DESC_0_OWN into the ring descriptor for every slot beyond old_head as soon as that slot's memset()'d local copy is committed with "*tx_desc_addr = tx_desc", i.e. before the buffers for that slot have necessarily all been mapped successfully. If emac_tx_map_frag() then fails on a later fragment, the err_free_skb path calls emac_free_tx_buf() to unmap and drop the skb, but leaves the already-written descriptor memory untouched, and tx_ring->head is never advanced past old_head (the "tx_ring->head = head" store is skipped by the goto). So a slot between old_head and the rolled-back head can be left with TX_DESC_0_OWN set and buffer_addr_{1,2} pointing at DMA mappings that emac_free_tx_buf() just tore down, while software considers that slot free again. The next successful emac_tx_mem_map() call only rebuilds old_head itself; if the DMA engine auto-advances into the following descriptor once it finishes old_head's packet, it will fetch that stale, already-unmapped address. emac_tx_clean_desc() already treats emac_free_tx_buf() and clearing the descriptor as a pair when reclaiming completed descriptors; do the same in the mapping failure path.
Title net: spacemit: clear TX descriptor on fragment mapping failure
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-10-19T09:22:17.811Z

Reserved: 2026-09-25T10:25:14.359Z

Link: CVE-2026-98592

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-18T16:17:11.830

Modified: 2026-10-19T10:19:20.360

Link: CVE-2026-98592

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-10-18T00:00:00Z

Links: CVE-2026-98592 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-20T21:30:17Z

Weaknesses
  • CWE-825

    Expired Pointer Dereference