NULL Pointer Dereference in OpenSSL Password-Based CMS Decryption
CVE-2026-42766 is a NULL pointer dereference vulnerability in OpenSSL's handling of password-based CMS decryption. A specially crafted password-encrypted CMS message can omit the optional ASN.1 field PasswordRecipientInfo.keyDerivationAlgorithm. During CMS decryption, the OpenSSL CMS implementation dereferences this field without first verifying that it is present, causing a NULL pointer dereference. The issue affects applications that process attacker-supplied password-encrypted CMS messages using OpenSSL CMS decryption functionality.
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Impact, mitigation & remediation
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
Impact
What an attacker gets, and what they’ve been doing with it.
Mitigation
If you can’t patch tonight, do this now.
Remediation
Patch, then assume compromise.
Exploits
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
Affected products & vendors
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
8 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
An OpenSSL vulnerability addressed in Alpine Linux 3.24.1 as part of the June 9, 2026 advisory.
A low-severity OpenSSL NULL pointer dereference in password-based CMS decryption caused by dereferencing an optional absent keyDerivationAlgorithm field, leading to denial of service.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.