What’s Vulnerable › Vulnerabilities

CVE-2018-15836

• Severity: high (CVSS 7.5 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2018-09-26 · updated 2026-06-17
• Weakness: CWE-347

Description

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

How to fix

Upgrade to a fixed version: Xelerance Openswan 2.6.50.1. Check the vendor advisory for mitigations.

References

• https://github.com/xelerance/Openswan/commit/0b460be9e287fd335c8ce58129c67bf06065ef51
• https://github.com/xelerance/Openswan/commit/9eaa6c2a823c1d2b58913506a15f9474bf857a3d
• https://lists.openswan.org/pipermail/users/2018-August/023761.html
• https://github.com/xelerance/Openswan/commit/0b460be9e287fd335c8ce58129c67bf06065ef51
• https://github.com/xelerance/Openswan/commit/9eaa6c2a823c1d2b58913506a15f9474bf857a3d
• https://lists.openswan.org/pipermail/users/2018-August/023761.html

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