CVE-2026-10097
ML-KEM-1024 x64 AVX2 incomplete cipher text comparison enables IND-CCA2 break and static private-key recovery
Published Jun 25, 2026
CVSS 4.0 · 8.3 High
EPSS < 1%
KEV · Not listed
Description
wolfSSL's AVX2-optimized ML-KEM implementation (mlkem_cmp_avx2) compares only 1536 of the 1568 ciphertext bytes during the Fujisaki-Okamoto re-encryption check in ML-KEM-1024 decapsulation. Ciphertexts that differ from the expected re-encryption solely in bytes 1536-1567 bypass implicit rejection and are accepted as valid, breaking IND-CCA2 security. An attacker able to submit chosen ciphertexts to a decapsulation oracle that uses a static ML-KEM-1024 key, and to observe whether the genuine shared secret or the implicit-rejection secret was produced, can use this as a plaintext-checking oracle to recover the private key. A proof of concept recovered a full ML-KEM-1024 private key with approximately 98% success using roughly 350 chosen ciphertexts. The flaw is a deterministic logic error and does not rely on timing measurements.
Affected Products
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CVE record
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NVD configurations
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Red Hat packages
No data
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OpenCVE enrichment
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
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| wolfSSL | wolfSSL | unaffected |
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No data.
| Vendor | Product | Versions | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Wolfssl | Wolfssl |
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Remediation
Tracking
Advisories
Metrics
Attack Vector Network
Attack Complexity High
Privileges Required None
Attack Requirements Present
User Interaction None
Vulnerable System Confidentiality Impact High
Vulnerable System Integrity Impact Low
Vulnerable System Availability Impact None
Subsequent System Confidentiality Impact None
Subsequent System Integrity Impact None
Subsequent System Availability Impact None
Attack Vector Network
Attack Complexity Low
Privileges Required None
Scope Unchanged
Confidentiality Impact High
Integrity Impact None
Availability Impact None
User Interaction None
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.262% probability within 30 days)
Exploitation none
Automatable no
Technical Impact partial
References
History
Jun 26, 2026 4:45 PM
Description updated. Title updated. Weaknesses updated. Scoring metrics updated
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| Description | ML-KEM-1024 x64 AVX2 implicit rejection failure in the Fujisaki-Okamoto transform breaks IND-CCA2 security, allowing decapsulation to deviate from the implicit-rejection behavior required by the standard. The AVX2 constant-time ciphertext comparison used during decapsulation never compared the final 32-byte block of the 1568-byte ML-KEM-1024 ciphertext, so a ciphertext manipulated only in those final bytes would compare as equal and decapsulation returned the real shared secret instead of performing the required implicit rejection. | wolfSSL's AVX2-optimized ML-KEM implementation (mlkem_cmp_avx2) compares only 1536 of the 1568 ciphertext bytes during the Fujisaki-Okamoto re-encryption check in ML-KEM-1024 decapsulation. Ciphertexts that differ from the expected re-encryption solely in bytes 1536-1567 bypass implicit rejection and are accepted as valid, breaking IND-CCA2 security. An attacker able to submit chosen ciphertexts to a decapsulation oracle that uses a static ML-KEM-1024 key, and to observe whether the genuine shared secret or the implicit-rejection secret was produced, can use this as a plaintext-checking oracle to recover the private key. A proof of concept recovered a full ML-KEM-1024 private key with approximately 98% success using roughly 350 chosen ciphertexts. The flaw is a deterministic logic error and does not rely on timing measurements. |
| Title | ML-KEM-1024 x64 AVX2 implicit rejection failure breaks IND-CCA2 security | ML-KEM-1024 x64 AVX2 incomplete cipher text comparison enables IND-CCA2 break and static private-key recovery |
| Weaknesses | CWE-327 | CWE-697 |
| Metrics |
cvssV4_0
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cvssV4_0
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Jun 26, 2026 2:30 PM
Scoring metrics updated
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
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Jun 26, 2026 1:30 AM
First appearance in the feed. Affected vendors updated
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Wolfssl
Wolfssl wolfssl |
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| Vendors & Products |
Wolfssl
Wolfssl wolfssl |
Jun 25, 2026 8:15 PM
Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| Description | ML-KEM-1024 x64 AVX2 implicit rejection failure in the Fujisaki-Okamoto transform breaks IND-CCA2 security, allowing decapsulation to deviate from the implicit-rejection behavior required by the standard. The AVX2 constant-time ciphertext comparison used during decapsulation never compared the final 32-byte block of the 1568-byte ML-KEM-1024 ciphertext, so a ciphertext manipulated only in those final bytes would compare as equal and decapsulation returned the real shared secret instead of performing the required implicit rejection. | |
| Title | ML-KEM-1024 x64 AVX2 implicit rejection failure breaks IND-CCA2 security | |
| Weaknesses | CWE-327 | |
| References |
| |
| Metrics |
cvssV4_0
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Weaknesses
