CVE-2026-23390 tracing/dma: Cap dma_map_sg tracepoint arrays to prevent buffer overflow
A buffer overflow in the Linux kernel's DMA tracing can cause a denial of service when tracing large scatter-gather lists.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-23390?
CVE-2026-23390 is a high-severity memory corruption vulnerability in Linux kernel, published on 25 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
tracing/dma: Cap dma_map_sg tracepoint arrays to prevent buffer overflow
The dma_map_sg tracepoint can trigger a perf buffer overflow when tracing large scatter-gather lists. With devices like virtio-gpu creating large DRM buffers, nents can exceed 1000 entries, resulting in:
phys_addrs: 1000 * 8 bytes = 8,000 bytes dma_addrs: 1000 * 8 bytes = 8,000 bytes lengths: 1000 * 4 bytes = 4,000 bytes Total: ~20,000 bytes
This exceeds PERF_MAX_TRACE_SIZE (8192 bytes), causing:
WARNING: CPU: 0 PID: 5497 at kernel/trace/trace_event_perf.c:405 perf buffer not large enough, wanted 24620, have 8192
Cap all three dynamic arrays at 128 entries using min() in the array size calculation. This ensures arrays are only as large as needed (up to the cap), avoiding unnecessary memory allocation for small operations while preventing overflow for large ones.
The tracepoint now records the full nents/ents counts and a truncated flag so users can see when data has been capped.
Changes in v2: - Use min(nents, DMA_TRACE_MAX_ENTRIES) for dynamic array sizing instead of fixed DMA_TRACE_MAX_ENTRIES allocation (feedback from Steven Rostedt) - This allocates only what's needed up to the cap, avoiding waste for small operations
Reviwed-by: Sean Anderson <[email protected]>
Weakness: CWE-787
Which versions are affected by CVE-2026-23390?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-23390?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-23390 being exploited?
There is no known exploitation of CVE-2026-23390 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-23390, DEBIAN-CVE-2026-23390, GHSA-qf3f-hxv9-hpx7, ROOT-OS-UBUNTU-2204-CVE-2026-23390, ROOT-OS-UBUNTU-2404-CVE-2026-23390, UBUNTU-CVE-2026-23390.