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CVE-2026-75805 on Cyberus Linux 26.05

Aliases: CVE-2026-75805

Packages: openssl_3_6

Status: Resolved

Advisory Information

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 ' 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.

Updates

2026-10-09 02:48 CEST

Metadata changes:

  • Status for package openssl_3_6: “Resolved” (257cd5b258336d6254b2bf4b5c12156b7b8f8821)

2026-10-05 16:30 CEST

Metadata changes:

  • Status for package openssl_3_6: “In Progress” (257cd5b258336d6254b2bf4b5c12156b7b8f8821)

(Amended on: 2026-10-05 16:31 CEST)

2026-10-05 16:28 CEST

Metadata changes:

  • Status for package openssl_3: “Package not supported” (1f5405d51c08776fb35a8dd8ecc33da81cb52f42)

Comment:

OpenSSL 3.0 has reached EOL status and will not receive further security updates.

2026-10-05 16:27 CEST

Metadata changes:

  • Status for package openssl_3_5: “Resolved” (1f5405d51c08776fb35a8dd8ecc33da81cb52f42)

2026-10-05 16:27 CEST

Metadata changes:

  • Status for package openssl_4_0: “Resolved” (1f5405d51c08776fb35a8dd8ecc33da81cb52f42)

2026-10-01 01:19 CEST

Metadata changes:

  • Status for package openssl_3_5: “In Progress” (1f5405d51c08776fb35a8dd8ecc33da81cb52f42)

2026-10-01 01:18 CEST

Metadata changes:

  • Status for package openssl_4_0: “In Progress” (77f391603c7ef9448f3b3cb5d9aa3b01783836d6)

2026-09-30 09:55 CEST

Metadata changes:

  • Status for package openssl_3_5: “In Progress” (1f5405d51c08776fb35a8dd8ecc33da81cb52f42)

2026-09-29 19:52 CEST

Metadata changes:

  • Status for package openssl_3: “Plausible”
  • Status for package openssl_3_5: “Plausible”
  • Status for package openssl_3_6: “Plausible”
  • Status for package openssl_4_0: “Plausible”

(Amended on: 2026-09-29 19:53 CEST)

2026-09-29 19:24 CEST

Metadata changes:

  • Status for package openssl_3: “New”
  • Status for package openssl_3_5: “New”
  • Status for package openssl_3_6: “New”
  • Status for package openssl_4_0: “New”