CVE-2026-43031: net: xilinx: axienet: Fix BQL accounting for multi-BD TX packets

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-01 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: net: xilinx: axienet: Fix BQL accounting for multi-BD TX packets When a TX packet spans multiple buffer descriptors (scatter-gather), axienet_free_tx_chain sums the per-BD actual length from descriptor status into a caller-provided accumulator. That sum is reset on each NAPI poll. If the BDs for a single packet complete across different polls, the earlier bytes are lost and never credited to BQL. This causes BQL to think bytes are permanently in-flight, eventually stalling the TX queue. The SKB pointer is stored only on the last BD of a packet. When that BD completes, use skb->len for the byte count instead of summing per-BD status lengths. This matches netdev_sent_queue(), which debits skb->len, and naturally survives across polls because no partial packet contributes to the accumulator.

Affected products

Linux kernel: from 6.15 before 6.18.22; from 6.19 before 6.19.12; 7.0-rc1, 7.0-rc2, 7.0-rc3, 7.0-rc4, 7.0-rc5, 7.0-rc6 — fixed in 6.18.22, 6.19.12

How to fix

Upgrade to a fixed version: Linux kernel 6.18.22, 6.19.12. Check the vendor advisory for mitigations.

References

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