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.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | strongswan | 5.7.0-1 | — |
| Debian 13 | strongswan | 5.7.0-1 | — |
| Debian 12 | strongswan | 5.7.0-1 | — |
| Debian 9 | strongswan | 5.5.1-4+deb9u3 | DSA-4305-1 |
| Debian 8 | strongswan | 5.2.1-6+deb8u7 | DLA-1522-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | strongswan | 5.6.2-1ubuntu2.2 | USN-3771-1 |
| Ubuntu 16.04 LTS | strongswan | 5.3.5-1ubuntu3.7 | USN-3771-1 |
| Ubuntu 14.04 LTS | strongswan | 5.1.2-0ubuntu2.10 | USN-3771-1 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP1 | strongswan | 5.6.0-4.3.2 | SUSE-SU-2019:3056-1 |
| SLES 15 | strongswan | 5.6.0-4.3.2 | SUSE-SU-2019:3056-1 |
| SLES 12 SP5 | strongswan | 5.1.3-26.13.1 | SUSE-SU-2019:3266-1 |
| SLES 12 SP4 | strongswan | 5.1.3-26.13.1 | SUSE-SU-2019:3266-1 |
| SLES 12 SP3 | strongswan | 5.1.3-26.13.1 | SUSE-SU-2019:3266-1 |
Show 12 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP2 | strongswan | 5.1.3-26.13.1 | SUSE-SU-2019:3266-1 |
| SLES 12 SP1 | strongswan | 5.1.3-26.13.1 | SUSE-SU-2019:3266-1 |
| SLES 11 SP4 | strongswan | 4.4.0-6.36.12.1 | SUSE-SU-2022:14887-1 |
| SLES for SAP 12 SP5 | strongswan | 5.1.3-26.13.1 | SUSE-SU-2019:3266-1 |
| SLES for SAP 12 SP4 | strongswan | 5.1.3-26.13.1 | SUSE-SU-2019:3266-1 |
| SLES for SAP 12 SP3 | strongswan | 5.1.3-26.13.1 | SUSE-SU-2019:3266-1 |
| SLES for SAP 12 SP2 | strongswan | 5.1.3-26.13.1 | SUSE-SU-2019:3266-1 |
| SLES for SAP 12 SP1 | strongswan | 5.1.3-26.13.1 | SUSE-SU-2019:3266-1 |
| SUSE OpenStack Cloud 8 | strongswan | 5.1.3-26.13.1 | SUSE-SU-2019:3266-1 |
| SUSE OpenStack Cloud 7 | strongswan | 5.1.3-26.13.1 | SUSE-SU-2019:3266-1 |
| SUSE Linux Enterprise Point of Sale 11 SP3 | strongswan | 4.4.0-6.36.12.1 | SUSE-SU-2022:14887-1 |
| SUSE Enterprise Storage 5 | strongswan | 5.1.3-26.13.1 | SUSE-SU-2019:3266-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.1 | strongswan | 5.6.0-lp151.4.3.1 | openSUSE-SU-2019:2598-1 |
| openSUSE Leap 15.0 | strongswan | 5.6.0-lp150.3.3.1 | openSUSE-SU-2019:2594-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | strongswan | 5.7.0-r0 | — |
| Alpine v3.23 | strongswan | 5.7.0-r0 | — |
| Alpine v3.22 | strongswan | 5.7.0-r0 | — |
| Alpine v3.21 | strongswan | 5.7.0-r0 | — |
| Alpine v3.20 | strongswan | 5.7.0-r0 | — |
Show 15 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | strongswan | 5.7.0-r0 | — |
| Alpine v3.18 | strongswan | 5.7.0-r0 | — |
| Alpine v3.17 | strongswan | 5.7.0-r0 | — |
| Alpine v3.16 | strongswan | 5.7.0-r0 | — |
| Alpine v3.15 | strongswan | 5.7.0-r0 | — |
| Alpine v3.14 | strongswan | 5.7.0-r0 | — |
| Alpine v3.13 | strongswan | 5.7.0-r0 | — |
| Alpine v3.12 | strongswan | 5.7.0-r0 | — |
| Alpine v3.11 | strongswan | 5.7.0-r0 | — |
| Alpine v3.10 | strongswan | 5.7.0-r0 | — |
| Alpine v3.9 | strongswan | 5.7.0-r0 | — |
| Alpine v3.8 | strongswan | 5.6.3-r2 | — |
| Alpine v3.7 | strongswan | 5.6.3-r1 | — |
| Alpine v3.6 | strongswan | 5.5.3-r2 | — |
| Alpine v3.5 | strongswan | 5.5.3-r2 | — |
Advisories 8
- DSA-4305-1 strongswan - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-1522-1 strongswan - security update Debian Security (DSA / DLA) · Mar 9, 2026
- USN-3771-1 strongswan vulnerabilities Ubuntu Security Notices (USN) · Feb 10, 2026
- openSUSE-SU-2019:2598-1 Security update for strongswan SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2022:14887-1 Security update for strongswan SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:3056-1 Security update for strongswan SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2019:2594-1 Security update for strongswan SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:3266-1 Security update for strongswan SUSE / openSUSE Security Updates · Feb 4, 2026
References
- DSA-4305 vendor-advisory
- GLSA-201811-16 vendor-advisory
- https://www.strongswan.org/blog/2018/09/24/strongswan-vulnerability-%28cve-2018-16151%2C-cve-2018-16152%29.html
- [debian-lts-announce] 20180926 [SECURITY] [DLA 1522-1] strongswan security update mailing-list
- USN-3771-1 vendor-advisory
- openSUSE-SU-2019:2594 vendor-advisory
- openSUSE-SU-2019:2598 vendor-advisory
- openSUSE-SU-2020:0403 vendor-advisory