CVE-2026-33662Network attack vector

Remote crash via wrapped RSA padding length

Published Apr 24, 2026 · Updated Apr 24, 2026

Integer underflow in OP-TEE OS 3.8.0 through 4.10 allows remote attackers to crash the trusted OS with a small RSA modulus. The emsa_pkcs1_v1_5_encode() function subtracts digest and encoding overhead from the modulus size without checking for underflow, then passes the wrapped padding length to memset(), which overwrites heap memory with 0xFF bytes. The path is reachable only on platforms with RSA acceleration registered; exploitation interrupts secure-world services by crashing OP-TEE.

CVSS severity7.5
High
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer underflow in OP-TEE OS 3.8.0 through 4.10 allows remote attackers to crash the trusted OS with a small RSA modulus. The emsa_pkcs1_v1_5_encode() function subtracts digest and encoding overhead from the modulus size without checking for underflow, then passes the wrapped padding length to memset(), which overwrites heap memory with 0xFF bytes. The path is reachable only on platforms with RSA acceleration registered; exploitation interrupts secure-world services by crashing OP-TEE.

The record

CVE
CVE-2026-33662
Published
Apr 24, 2026
Updated
Apr 24, 2026
Vendor
OP-TEE
Product
OP-TEE OS
Classifications
CWE-190, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 24, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 3.8.0, <= 4.10

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OP-TEE · OP-TEE OSversion=>= 3.8.0, <= 4.10

Published CVSS scores

7.5GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-190Integer Overflow or Wraparound
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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