CVE-2018-16151

strongswan: authentication bypass in verify_emsa_pkcs1_signature() in gmp_rsa_public_key.c

Published Sep 26, 2018 CVSS 3.1 · 7.5 High EPSS 1.9% KEV · Not listed
Description
In verify_emsa_pkcs1_signature() in gmp_rsa_public_key.c in the gmp plugin in strongSwan 4.x and 5.x before 5.7.0, the RSA implementation based on GMP does not reject excess data after the encoded algorithm OID during PKCS#1 v1.5 signature verification. Similar to the flaw in the same version of strongSwan regarding digestAlgorithm.parameters, a remote attacker can forge signatures when small public exponents are being used, which could lead to impersonation when only an RSA signature is used for IKEv2 authentication.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-1522-1 strongswan security update
Debian DSA Debian DSA DSA-4305-1 strongswan security update
Debian DSA Debian DSA DSA-4309-1 strongswan security update
EUVD EUVD EUVD-2018-8006 In verify_emsa_pkcs1_signature() in gmp_rsa_public_key.c in the gmp plugin in strongSwan 4.x and 5.x before 5.7.0, the RSA implementation based on GMP does not reject excess data after the encoded algorithm OID during PKCS#1 v1.5 signature verification. Similar to the flaw in the same version of strongSwan regarding digestAlgorithm.parameters, a remote attacker can forge signatures when small public exponents are being used, which could lead to impersonation when only an RSA signature is used for IKEv2 authentication.
Ubuntu USN Ubuntu USN USN-3771-1 strongSwan vulnerabilities
History
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'}

ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
mitre
Published
Updated
Dec 3, 2025, 8:26 PM
Reserved
Aug 29, 2018, 12:00 AM
Status
Modified
Published
Sep 26, 2018, 9:29 PM
Modified
Jun 17, 2026, 1:43 AM
Severity
Moderate
Public date
Sep 24, 2018, 12:00 AM