CVE-2026-50722
CVE-2026-50722 · IKEv2 Denial of Service via RSA-SHA1 (PKCS#1 RSASSA-PKCS1-v1_5) authentication payload
This page contains facts from public vulnerability sources. Check the original advisory before updating.
Libreswan, via the function RSA_authenticate_hash_signature_pkcs1_1_5_rsa(), did not correctly verify the DER encoding of the ASN.1 digest when the IKEv2 AUTH payload was encoded using RSASSA-PKCS1-v1_5 (RFC 8017). A remote attacker can use a variation on the Bleichenbacher attack to forge the AUTH payload when small public exponents are used (e.g., e=3), leading to impersonation. Additionally, a remote attacker, by encoding a shorter than expected hash in the AUTH payload, could trigger an assertion leading to denial-of-service. The daemon aborts and restarts; continued exploitation causes sustained denial of service. Remote code execution is not possible. X.509 certificate verifications of the remote IKE peer are not affected.
CVSS 7.5 · High · EPSS 0.3% · Fix available
- Published
- Updated
Stack: system
Affected products and versions
libreswan
- Versions
- ≥ 0, ≤ 5.3: Affected (semver)
- 5.3.1: Not affected (semver)
No fix published
libreswan Debian:12
- Versions
- 4.10-2
- 4.10-2+deb12u1
- 4.11-1
- 4.12-1
- 4.12-2
- 4.12-3
- 4.14-1
- 4.14-1.1
- 4.15-1
- 5.0~rc2-1
- 5.0~rc2-2
- 5.2-1
- 5.2-2
- 5.2-2.1
- 5.2-2.2
- 5.2-2.3
- 5.2-2.4
- 5.2-2.5
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
libreswan Debian:13
- Versions
- 5.2-2.2
- 5.2-2.3
- 5.2-2.4
- 5.2-2.5
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
libreswan Debian:14
- Versions
- 5.2-2.2
- 5.2-2.3
- 5.2-2.4
- Affected ranges
- ECOSYSTEM: < 5.2-2.5
Update to 5.2-2.5
libreswan Ubuntu:18.04:LTS
- Versions
- 3.20-7build1
- 3.21-2
- 3.22-1
- 3.22-2
- 3.22-3
- 3.22-4
- 3.23-1
- 3.23-4
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
libreswan Ubuntu:20.04:LTS
- Versions
- 3.29-2
- 3.29-2build1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
libreswan Ubuntu:22.04:LTS
- Versions
- 3.32-3ubuntu3
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
libreswan Ubuntu:24.04:LTS
- Versions
- 4.11-1ubuntu1
- 4.12-1ubuntu1
- 4.14-1ubuntu1
- 4.14-1ubuntu2
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
libreswan Ubuntu:25.10
- Versions
- 4.14-1ubuntu2
- 5.2-2.2ubuntu1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
libreswan Ubuntu:26.10
- Versions
- 5.2-2.2ubuntu2
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
libreswan Ubuntu:26.04:LTS
- Versions
- 5.2-2.2ubuntu1
- 5.2-2.2ubuntu2
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published