Is CVE-2026-33662 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-33662 being exploited in the wild.

How severe is CVE-2026-33662?

High severity, with a CVSS score of 7.5, published 24 April 2026.

Which products and versions are affected?

TrustedFirmware OP-TEE OS 3.8.0 to 4.10.0.

Is there a fix for CVE-2026-33662?

A patch was published on 2026-04-24: Fix published in version 4.11.0 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-33662 attacked?

It is attacked over the network, in device firmware.

Am I affected by CVE-2026-33662?

Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-33662: OP-TEE OS integer underflow in RSASSA-PKCS1-v1_5 encoding

CVE-2026-33662 · Severity: high · CVSS 7.5 · Published 2026-04-24

OP-TEE is a secure operating system used on Arm-based devices to protect sensitive data and cryptographic operations. A flaw in how it handles certain digital signature tasks allows an attacker to trigger a system crash by providing a specially crafted cryptographic key. This results in a denial-of-service, potentially disrupting secure device operations or causing the entire system to reboot.

Quick answers

Is CVE-2026-33662 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-33662 being exploited in the wild.
How severe is CVE-2026-33662?: High severity, with a CVSS score of 7.5, published 24 April 2026.
Which products and versions are affected?: TrustedFirmware OP-TEE OS 3.8.0 to 4.10.0.
Is there a fix for CVE-2026-33662?: A patch was published on 2026-04-24: Fix published in version 4.11.0 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-33662 attacked?: It is attacked over the network, in device firmware.
Am I affected by CVE-2026-33662?: Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

An integer underflow vulnerability exists in the emsa_pkcs1_v1_5_encode() function within core/drivers/crypto/crypto_api/acipher/rsassa.c. The vulnerability occurs when calculating the padding size (PS size) for RSASSA-PKCS1-v1_5 encoding; specifically, subtracting the digest and metadata sizes from a small RSA modulus results in a negative value stored in an unsigned integer. This underflowed value is subsequently passed to memset(), causing a massive heap overwrite with 0xFF bytes until the Trusted Execution Environment (TEE) crashes. The issue specifically affects platforms with RSA acceleration enabled, such as those using NXP CAAM, HiSilicon ACC_V3, or Versal crypto drivers. A fix is available in OP-TEE version 4.11.0.

Affected products

TrustedFirmware OP-TEE OS 3.8.0 to 4.10.0

Timeline

2025-12-24: other: Report received by vendor
2026-01-07: other: Confirmed as security issue
2026-04-24: patched: Fix published in version 4.11.0
2026-04-24: advisory: Public disclosure

References

https://github.com/OP-TEE/optee_os/security/advisories/GHSA-4cf8-v5g3-73gr

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.