VulnerabilityAwaiting Analysis

CVE-2026-82876

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.

CRITICAL 9.3EPSS 0.09%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.09%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

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.

CVSS 4.0: 9.3 CRITICALCVSS: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/M
EPSS: 0.09% probability · 0th percentile
CISA KEV: Not listed
Weakness: CWE-347
Source: disclosure@vulncheck.com

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.