CVE-2018-15836

Name: CVE-2018-15836
Creator: NVD / NIST
Published: 2018-09-26T21:29:00.913+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

UnknownEPSS 1.49%

Last modified Jun 17, 2026

CVE-2018-15836 is a vulnerability of currently unknown severity. 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. EPSS estimates a 1.49% chance of exploitation in the next 30 days.

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.

Metrics

EPSS Probability

1.49%

70.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-347

Affected Software

Vendor	Product	Versions
Xelerance	Openswan	< 2.6.50.1

References

https://github.com/xelerance/Openswan/commit/0b460be9e287fd335c8ce58129c67bf06065ef51Patch, Vendor Advisory
https://github.com/xelerance/Openswan/commit/9eaa6c2a823c1d2b58913506a15f9474bf857a3dPatch, Vendor Advisory
https://lists.openswan.org/pipermail/users/2018-August/023761.htmlRelease Notes, Vendor Advisory
https://github.com/xelerance/Openswan/commit/0b460be9e287fd335c8ce58129c67bf06065ef51Patch, Vendor Advisory
https://github.com/xelerance/Openswan/commit/9eaa6c2a823c1d2b58913506a15f9474bf857a3dPatch, Vendor Advisory
https://lists.openswan.org/pipermail/users/2018-August/023761.htmlRelease Notes, Vendor Advisory

Timeline

Published: Sep 26, 2018
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2018-15836?

How severe is CVE-2018-15836?

Severity scoring for CVE-2018-15836 is pending analysis. The EPSS model estimates a 1.49% probability of exploitation in the next 30 days.

How do I fix CVE-2018-15836?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2018-15836?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST