Integer Overflow or Wraparound Affecting optee-os package, versions <4.10.0-1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-DEBIANUNSTABLE-OPTEEOS-16290964
- published25 Apr 2026
- disclosed24 Apr 2026
Introduced: 24 Apr 2026
CVE-2026-33662 (opens in a new tab)How to fix?
Upgrade Debian:unstable optee-os to version 4.10.0-1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream optee-os package and not the optee-os package as distributed by Debian.
See How to fix? for Debian:unstable relevant fixed versions and status.
OP-TEE is a Trusted Execution Environment (TEE) designed as companion to a non-secure Linux kernel running on Arm; Cortex-A cores using the TrustZone technology. From 3.8.0 to 4.10, in the function emsa_pkcs1_v1_5_encode() in core/drivers/crypto/crypto_api/acipher/rsassa.c, the amount of padding needed, "PS size", is calculated by subtracting the size of the digest and other fields required for the EMA-PKCS1-v1_5 encoding from the size of the modulus of the key. By selecting a small enough modulus, this subtraction can overflow. The padding is added as a string of 0xFF bytes with a call to memset(), and an underflowed integer will cause the memset() call to overwrite until OP-TEE crashes. This only affects platforms registering RSA acceleration.