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CVE-2026-42766

Possible NULL Dereference in Password-Based CMS Decryption

Published
Last modified
published
Not listed in CISA KEV
Low (openssl)
Fix
Fixed in 4.0.1, 3.6.3, 3.5.7, 3.4.6, 3.0.21, and 2 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • OpenSSL OpenSSL

    From 4.0.0 · fixed in 4.0.1; From 3.6.0 · fixed in 3.6.3; From 3.5.0 · fixed in 3.5.7; From 3.4.0 · fixed in 3.4.6; From 3.0.0 · fixed in 3.0.21; From 1.1.1 · fixed in 1.1.1zh; From 1.0.2 · fixed in 1.0.2zq

References 6

openssl-library.org

GitHub · openssl/openssl