CVE-2026-42766

Summary

Issue summary: A specially crafted password-encrypted CMS message can trigger a NULL pointer dereference during CMS decryption.

Impact summary: This NULL pointer dereference leads to an application crash and a Denial of Service.

The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as OPTIONAL in the ASN.1 specification and may therefore be absent in specially crafted inputs. During the password-based CMS decryption the OpenSSL CMS implementation dereferences this field without first checking whether it was present.

An attacker who supplies such a CMS message to an application performing password-based CMS decryption can trigger an application crash, leading to a Denial of Service.

Applications that process password-encrypted CMS messages may be affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.

Affected Software

VendorProductVersion RangeStatus
OpenSSLOpenSSL4.0.0 < 4.0.1affected
OpenSSLOpenSSL3.6.0 < 3.6.3affected
OpenSSLOpenSSL3.5.0 < 3.5.7affected
OpenSSLOpenSSL3.4.0 < 3.4.6affected
OpenSSLOpenSSL3.0.0 < 3.0.21affected
OpenSSLOpenSSL1.1.1 < 1.1.1zhaffected
OpenSSLOpenSSL1.0.2 < 1.0.2zqaffected

Weaknesses

  • CWE-476: CWE-476 NULL Pointer Dereference

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References