CVE-2026-82876

9.3 criticalEPSS 0.1%

Critical (9.3). EPSS 0.1% chance of exploitation in the next 30 days.

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.

Severity

CVSS 4.0

9.3 critical

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

CVSS 3.1

8.2 high

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

EPSS: 0.1% chance of exploitation in the next 30 days; higher than 1% of CVEs (scores of 2026-10-31)
CWE: CWE-347
Published: 2026-08-31
Modified: 2026-09-10
Record from: the NVD, synced 2026-10-19

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

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