Executive brief
The Phison PS3111-S11 SATA SSD controller is a storage device component used in over 100 million SSDs from multiple vendors. The controller verifies firmware authenticity using RSA signatures, but the verification check uses a public key embedded within the firmware image itself rather than a fixed key in immutable hardware storage. An attacker with physical access to the drive can create malicious firmware, sign it with their own RSA key, embed that key in the signature area, and the controller will accept the tampered firmware as legitimate—potentially allowing persistent malware installation, data theft, or drive corruption.
Technical details
The vulnerability is a cryptographic signature validation bypass in the Phison PS3111-S11 bootloader. The bootloader loads and verifies firmware images from NAND flash, but the RSA public modulus used to verify firmware signatures is read from a variable field within the firmware image header itself rather than being anchored in immutable mask ROM or eFuse-protected storage. An attacker with physical access can generate a new RSA key pair, create modified firmware, sign it with the private key, and embed the corresponding public modulus in the firmware header's signature segment. The bootloader will then accept the forged firmware as valid. The attack requires direct NAND flash access or exploitation of the bootloader's external firmware loading interface, but once executed allows arbitrary code execution in the SoC context with full access to DRAM and storage. The vulnerability affects numerous SSD models across multiple vendors that use the S11 controller.
Affected products
- Phison PS3111-S11 SSD controller All versions
Timeline
- 2026-08-31: disclosed: CVE-2026-82876 published on NVD