CMP client crash via absent algorithm parameters
Published Jun 9, 2026 · Updated Jun 9, 2026
NULL pointer dereference in OpenSSL CMP clients allows remote attackers to crash the client through a crafted CMP server response. The OSSL_CRMF_ENCRYPTEDVALUE_decrypt function passes a missing symmAlg parameter to ASN1_TYPE_get_octetstring without checking it for NULL. Exploitation requires processing a malicious CertRepMessage from an attacker-controlled CMP server or man-in-the-middle attackers; the bounded result is a client-process crash.
Summary
What happened
NULL pointer dereference in OpenSSL CMP clients allows remote attackers to crash the client through a crafted CMP server response. The OSSL_CRMF_ENCRYPTEDVALUE_decrypt function passes a missing symmAlg parameter to ASN1_TYPE_get_octetstring without checking it for NULL. Exploitation requires processing a malicious CertRepMessage from an attacker-controlled CMP server or man-in-the-middle attackers; the bounded result is a client-process crash.
The record
- CVE
- CVE-2026-42767
- Published
- Jun 9, 2026
- Updated
- Jun 9, 2026
- Vendor
- OpenSSL Project
- Product
- OpenSSL
- Classifications
- CWE-476, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 9, 2026CVE publishedPublication date reported by the CVE source.
- Jun 9, 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?
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- Affected versionversion=3.0.0 <3.0.21
- Affected versionversion=3.4.0 <3.4.6
- Affected versionversion=3.5.0 <3.5.7
- Affected versionversion=3.6.0 <3.6.3
- Affected versionversion=4.0.0 <4.0.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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