CVE intelligence and bounded remediation

CVE-2018-16151 — Strongswan Strongswan security vulnerability

High CVSS 7.5

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.

Severity
High
CVSS
7.5 (3.1)
Published
2018-09-26
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-347

Affected products

  • strongswan / strongswan
  • debian / debian_linux / 8.0
  • debian / debian_linux / 9.0
  • canonical / ubuntu_linux / 14.04
  • canonical / ubuntu_linux / 16.04
  • canonical / ubuntu_linux / 18.04

Showing 6 representative product identities from 7 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Cryptography, certificate, signature, and channel validation

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Inventory affected algorithms, key uses, trust stores, certificate validation settings, random sources, and plaintext channels across clients and services.
  • Determine which secrets, identities, signatures, or data protections depend on the affected primitive or validation path.
  • Check debug, compatibility, fallback, and hostname or audience override settings in build and runtime configuration.

Remediate safely

  • Use a maintained platform cryptographic API with approved algorithms, modes, parameters, randomness, and full peer identity validation.
  • Remove insecure fallback and validation bypasses; separate keys by purpose and load them from managed secret storage.
  • Plan rotation or reissuance for affected keys, certificates, tokens, hashes, or ciphertext and document compatibility sequencing.

Authoritative sources

Complete CVE record and remediation plan

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