CVE-2026-82876

critical · 9.3

Phison PS3111-S11 controller firmware verifies RSA signatures using a public modulus embedded within the firmware image itself rather than anchored in immutable storage. Attackers can generate arbitrary RSA key pairs, sign modified firmware with the private key, embed the matching modulus in the signature segment, and the controller accepts the tampered firmware as valid.

9.3

CVSS

0.1%

EPSS (exploit prob.)

2nd

EPSS percentile

2026-08-31

Published

CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Weaknesses

CWE-347

References

https://github.com/trulycrisp/psychite
https://trulycrisp.github.io/drivefirmware/phison_s11/
https://www.vulncheck.com/advisories/phison-ps3111-s11-controller-firmware-signature-verification-bypass

Query this programmatically:

curl https://evil-db.io/api/v1/cve/CVE-2026-82876