CVE-2018-15836: Xelerance Openswan

High severity, CVSS 7.5. EPSS: 1.5% chance of exploitation in the next 30 days.

In verify_signed_hash() in lib/liboswkeys/signatures.c in Openswan before 2.6.50.1, the RSA implementation does not verify the value of padding string during PKCS#1 v1.5 signature verification. Consequently, a remote attacker can forge signatures when small public exponents are being used. IKEv2 signature verification is affected when RAW RSA keys are used.

Affected products

• Xelerance Openswan: before 2.6.50.1 (fixed in 2.6.50.1)

Published 2018-09-26. Last modified 2026-06-17.