Executive brief
The Linux kernel's Tegra Security Engine crypto driver contains a buffer overflow vulnerability in its GCM (Galois/Counter Mode) authenticated encryption implementation. If an application performs GCM decryption without first calling the initialization function to set the authentication tag size, the driver calculates an incorrect buffer length, causing it to write beyond the allocated memory. This can lead to kernel crashes or potential privilege escalation on systems using Tegra processors with cryptographic acceleration.
Technical details
The vulnerability is a buffer overflow in tegra_gcm_do_one_req() within the Tegra Security Engine AES driver (drivers/crypto/tegra/tegra-se-aes.c). The root cause is an incorrect calculation of rctx->cryptlen during decryption operations; the function uses ctx->authsize (a context field that may be zero if tegra_gcm_setauthsize() was never called) instead of rctx->authsize from the request context. When ctx->authsize remains zero due to missing initialization, the decryption path performs a write operation beyond the bounds of rctx->dst_sg buffer. The attack vector is local and requires the ability to invoke crypto operations via the kernel's crypto API. The fix changes the calculation to use rctx->authsize and removes the unused ctx->authsize field entirely. Patches are available in mainline kernel commit 360f2974fcea49c61f6d6f81554741a9eeee7168 and corresponding stable releases.
Affected products
- Linux Linux kernel Tegra Security Engine driver (drivers/crypto/tegra)
Timeline
- 2026-08-26: disclosed
- 2026-07-30: patched: Fix merged to mainline kernel; backported to stable branches
- 2026-08-26: advisory: CVE published