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CVE-2026-75805— NULL Pointer Dereference in CMP Client Revocation Response Handling

Quick assessment

Affected
OpenSSL OpenSSL
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Issue summary: A CMP client that requests certificate revocation on the basis of a PKCS#10 CSR may dereference a NULL pointer and terminate abnormally when processing a crafted revocation response. Impact summary: The NULL pointer dereference happens on a read

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I. Basic Information for CVE-2026-75805

Vulnerability Information

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Vulnerability Title
NULL Pointer Dereference in CMP Client Revocation Response Handling
Source: CVE Program / CVE List V5
Vulnerability Description
Issue summary: A CMP client that requests certificate revocation on the basis of a PKCS#10 CSR may dereference a NULL pointer and terminate abnormally when processing a crafted revocation response. Impact summary: The NULL pointer dereference happens on a read which leads to a crash and a Denial of Service for the affected client application. CWE: CWE-476: NULL-pointer dereference Description: A CMP client revoking a certificate has to tell the server which certificate to revoke, and may do so by supplying a PKCS#10 CSR instead of the certificate itself or its issuer name and serial number. This is 'openssl cmp -cmd rr -csr <file>' on the command line, or OSSL_CMP_exec_RR_ses() with the certificate supplied via OSSL_CMP_CTX_set1_p10CSR() through the API. A CSR does not contain the issuer name and serial number of the certificate, so the client does not send them. A server may optionally name the certificate it revoked in its response, and the client then compares that name against what it sent. Having sent neither an issuer name nor a serial number, it has nothing to compare against, and a server returning a specially crafted name causes the client to read from a NULL pointer and crash. The revocation response is checked for valid message protection before the affected code is reached, so an attacker must be a malicious or compromised CMP server, or a man-in-the-middle in possession of the secret used for message protection. Clients that identify the certificate to be revoked by a certificate or by issuer and serial number rather than by a PKCS#10 CSR are not affected. FIPS impact: no No FIPS modules are affected by this issue, as the CMP protocol implementation is outside the OpenSSL FIPS module boundary.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
空指针解引用
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
OpenSSL OpenSSL 4.0.0 ~ 4.0.3 -

II. Public POCs for CVE-2026-75805

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III. Intelligence Information for CVE-2026-75805

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Other References for CVE-2026-75805 (5)

Same Patch Batch · OpenSSL · 2026-09-29 · 14 CVEs total

CVE-2026-35189 Excessive Memory Allocation in Relative CRLDP Processing
CVE-2026-35191 QUIC Unvalidated Amplification Credit may be Over Accounted
CVE-2026-75806 Unauthenticated and Undersized DTLS 1.2 AEAD Record Causes DoS
CVE-2026-75804 QUIC Connection-Level Flow Control is Not Enforced for Streams
CVE-2026-42772 Potential CPU DoS via O(n^2) Fragment Reassembly in QUIC
CVE-2026-54873 QUIC STREAM Fragment Metadata DoS
CVE-2026-54872 Timing Side-Channel in Scalar Multiplication for Non-NIST EC Curves
CVE-2026-54875 Non-Constant-Time SM2 Scalar Multiplication on ARM64 and RISC-V
CVE-2026-77696 Timing Side-Channel in SM2 Signature Generation
CVE-2026-72897 Out-of-Bounds Access After SSL_set_SSL_CTX() During a Handshake
CVE-2026-84782 DTLS Retransmits Handshake Messages From a Stale Buffer Offset
CVE-2026-84784 QUIC: Unbounded RETIRE_CONNECTION_ID Backlog
CVE-2026-84783 Use-After-Free in X.509 Extension Cache Under Concurrent Use

IV. Related Vulnerabilities

Same product: OpenSSL
Same vendor: OpenSSL
Same weakness: CWE-476

V. Comments for CVE-2026-75805

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