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Fencer Intel
high 7.5

CVE-2018-16151 json

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 b…

published 2018-09-26 8 y ago modified 2026-06-17 4 mo ago also EUVD-2018-8006

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.9%
EPSS 1.9% chance of exploitation in 30 days, percentile 79%
public exploits
0
none known

Summary

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.

Patch / fix

  • strongswan strongswan 5.7.0
  • strongswan Debian 14, Debian 13, Debian 12 5.7.0-1

debian advisories DEBIAN-CVE-2018-16151

  • strongswan Ubuntu 14.04 LTS 5.1.2-0ubuntu2.10
  • strongswan Ubuntu 16.04 LTS 5.3.5-1ubuntu3.7
  • strongswan Ubuntu 18.04 LTS 5.6.2-1ubuntu2.2

ubuntu advisories UBUNTU-CVE-2018-16151

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • strongswan SLES 11 SP4-LTSS, SLE Point of Sale 11 SP3 4.4.0-6.36.12.1
  • strongswan SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES for SAP 12 SP3 +13 more 5.1.3-26.13.1
  • strongswan SLE Module for Package Hub 15, SLE Module for Basesystem 15 SP1, SLE Module for Basesystem 15 5.6.0-4.3.2

suse advisories SUSE-SU-2022:14887-1SUSE-SU-2019:3266-1SUSE-SU-2019:3056-1

  • strongswan openSUSE Leap 15.1 5.6.0-lp151.4.3.1
  • strongswan openSUSE Leap 15.0 5.6.0-lp150.3.3.1

opensuse advisories openSUSE-SU-2019:2598-1openSUSE-SU-2019:2594-1

  • strongswan Alpine 3.24, Alpine 3.23, Alpine 3.22 +13 more 5.7.0-r0
  • strongswan Alpine 3.6, Alpine 3.5 5.5.3-r2
  • strongswan Alpine 3.7 5.6.3-r1
  • strongswan Alpine 3.8 5.6.3-r2

alpine advisories ALPINE-CVE-2018-16151

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • strongswan Arch Linux 5.7.0-1

arch linux advisories AVG-769

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2018-16151 updated cvss 5.6

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

  • Red Hat Enterprise Linux 7 strongimcv
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
11 mo ago

Exploit prediction

1.89% chance of exploitation in the next 30 days, higher than 79% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD 3.0 7.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:P/A:N

Classification

Weakness
  • CWE-347 Improper Verification of Cryptographic Signature

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.