CVE-2026-42766

NameCVE-2026-42766
DescriptionIssue 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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDSA-6335-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
openssl (PTS)bullseye1.1.1w-0+deb11u1vulnerable
bullseye (security)1.1.1w-0+deb11u7vulnerable
bookworm3.0.20-1~deb12u1vulnerable
bookworm (security)3.0.20-1~deb12u2fixed
trixie3.5.6-1~deb13u1vulnerable
trixie (security)3.5.6-1~deb13u2fixed
forky, sid3.6.2-1vulnerable

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
opensslsourcebookworm3.0.20-1~deb12u2DSA-6335-1
opensslsourcetrixie3.5.6-1~deb13u2DSA-6335-1
opensslsource(unstable)(unfixed)

Notes

https://openssl-library.org/news/secadv/20260609.txt
Fixed by: https://github.com/openssl/openssl/commit/3ff64913615d648cfbb6a6f1cf5529ae7ea829d7 (openssl-3.0.21)
Fixed by: https://github.com/openssl/openssl/commit/ba699b606969d20a108dda3cfe5422d4cc94eefb (openssl-3.0.21)

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