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CVE-2006-4339

Openssl: openssl: signature forgery via improper pkcs-1 padding removal leading to certificate validation bypass

Critical9.1EPSS 3.9%
Published
Updated
Reserved
Assigned by
redhat

Description

A flaw was found in OpenSSL. When configured to use an RSA key with exponent 3, OpenSSL improperly removes PKCS-1 padding before generating a hash. This allows remote attackers to forge PKCS #1 v1.5 signatures. Consequently, OpenSSL may incorrectly verify X.509 and other certificates, leading to a bypass of trust and authentication mechanisms.

Scores

CVSS scores of CVE-2006-4339, by who scored it
Scored byCVSSScoreVector
redhatCNA (assigner)3.1Critical9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
NVDNVD · Modified3.1Critical9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS (exploitation in 30 days)
3.9% · top 9.6% of all CVEs (4 Nov 2026)
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The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.1.

Weakness

Affected products

What to do

Workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

References (207)

Sources

The same CVE in the primary databases and aggregators, to check against.

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Record last updated .