DescriptionIssue summary: Checking excessively long DH keys or parameters may be very slow. Impact summary: Applications that use the functions DH_check(), DH_check_ex() or EVP_PKEY_param_check() to check a DH key or DH parameters may experience long delays. Where the key or parameters that are being checked have been obtained from an untrusted source this may lead to a Denial of Service. The function DH_check() performs various checks on DH parameters. After fixing CVE-2023-3446 it was discovered that a large q parameter value can also trigger an overly long computation during some of these checks. A correct q value, if present, cannot be larger than the modulus p parameter, thus it is unnecessary to perform these checks if q is larger than p. An application that calls DH_check() and supplies a key or parameters obtained from an untrusted source could be vulnerable to a Denial of Service attack. The function DH_check() is itself called by a number of other OpenSSL functions. An application calling any of those other functions may similarly be affected. The other functions affected by this are DH_check_ex() and EVP_PKEY_param_check(). Also vulnerable are the OpenSSL dhparam and pkeyparam command line applications when using the "-check" option. The OpenSSL SSL/TLS implementation is not affected by this issue. The OpenSSL 3.0 and 3.1 FIPS providers are not affected by this issue.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
openssl (PTS)buster1.1.1n-0+deb10u3vulnerable
buster (security)1.1.1n-0+deb10u6fixed
bullseye (security)1.1.1n-0+deb11u5vulnerable
sid, trixie3.0.11-1fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs


[bookworm] - openssl <postponed> (Minor issue, fix along with future DSA)
[bullseye] - openssl <postponed> (Minor issue, fix along with future DSA);a=commitdiff;h=1c16253f3c3a8d1e25918c3f404aae6a5b0893de (master);a=commitdiff;h=6a1eb62c29db6cb5eec707f9338aee00f44e26f5 (openssl-3.1.2);a=commitdiff;h=9002fd07327a91f35ba6c1307e71fa6fd4409b7f (openssl-3.0.10);a=commitdiff;h=91ddeba0f2269b017dc06c46c993a788974b1aa5 (OpenSSL_1_1_1v)

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