CVE-2025-22049

What it actually does

ARCH_DMA_MINALIGN default of 1 on LoongArch permits allocation of DMA buffers smaller than device requirements (e.g., APBDMA needing 16 bytes), allowing hardware to perform erroneous cacheline writes on undersized buffers.

Why it matters to the business

LoongArch-based systems risk memory corruption or instability during DMA operations involving small buffers, potentially disrupting device functionality and requiring architecture-specific updates across affected kernels.

How an attack unfolds

An attacker interacts with LoongArch hardware requiring DMA (such as APBDMA) to force allocation of small memory buffers via the kernel, triggering cacheline write errors that corrupt data or cause faults.

How to fix it

Update affected packages to the listed fixed versions, including libsoup 0:2.62.3-2.el8_4.1 across RHEL 8.4 variants and the Linux kernel commit f39af67f03b564b763b06e44cb960c10a382d54a; rebuild and reboot as required.

How to confirm the fix worked

Verify kernel configuration reports ARCH_DMA_MINALIGN >= 16, confirm package versions match the fixed releases, and test DMA operations with small buffers on LoongArch hardware.

Typical attack path

1. Identify LoongArch system with vulnerable kernel and DMA-capable devices
2. Trigger code paths that allocate small DMA buffers through device I/O or driver calls
3. Exploit resulting cacheline misalignment to induce hardware write errors
4. Leverage corruption for denial of service or further memory manipulation

How to detect it

Search kernel logs and dmesg for DMA alignment warnings or cacheline errors on LoongArch; inspect boot messages for ARCH_DMA_MINALIGN values below 16.

What your security team should do

• Prioritize kernel updates on all LoongArch systems within 30 days
• Audit DMA-using drivers and devices for small-buffer allocations
• Monitor for post-update stability in DMA-heavy workloads
• Review downstream dependents for similar alignment issues