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Vulnerability record · CVE-2018-15836 · published 26 September 2018

CVE-2018-15836: Xelerance openswan improper verification of cryptographic signature vulnerability

XXelerance · Openswan

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.

7.5 CVSS 3.0 High EPSS 1.5% · top 26.4% CWE-347 · Improper verification of cryptographic signature
7.5CVSS 3.0 base score, v2 5.0
1.5%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
6References
17 Jun 2026Last modified by NVD

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.

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/xelerance/Openswan/commit/0b460be9e287fd335c8ce58129c67bf06065ef51 PatchVendor Advisory
https://github.com/xelerance/Openswan/commit/9eaa6c2a823c1d2b58913506a15f9474bf857a3d PatchVendor Advisory
https://lists.openswan.org/pipermail/users/2018-August/023761.html Release NotesVendor Advisory
https://github.com/xelerance/Openswan/commit/0b460be9e287fd335c8ce58129c67bf06065ef51 PatchVendor Advisory
https://github.com/xelerance/Openswan/commit/9eaa6c2a823c1d2b58913506a15f9474bf857a3d PatchVendor Advisory
https://lists.openswan.org/pipermail/users/2018-August/023761.html Release NotesVendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

7.8CVE-2005-3671Frees wan vulnerabilityThe Internet Key Exchange version 1 (IKEv1) implementation in Openswan 2 (openswan-2) before 2.4.4, and freeswan in SUSE LINUX 9.1 before 2.04_1.5.4-…EPSS 7.5%7.2CVE-2005-0162Openswan vulnerabilityStack-based buffer overflow in the get_internal_addresses function in the pluto application for Openswan 1.x before 1.0.9, and Openswan 2.x before 2.…EPSS 1.7%6.8CVE-2013-2053Xelerance openswan memory buffer overflow vulnerabilityBuffer overflow in the atodn function in Openswan before 2.6.39, when Opportunistic Encryption is enabled and an RSA key is being used, allows remote…EPSS 2.4%6.5CVE-2010-3753Xelerance openswan os command injection vulnerabilityprograms/pluto/xauth.c in the client in Openswan 2.6.26 through 2.6.28 allows remote authenticated gateways to execute arbitrary commands via shell m…EPSS 2.4%6.5CVE-2010-3302Xelerance openswan memory buffer overflow vulnerabilityBuffer overflow in programs/pluto/xauth.c in the client in Openswan 2.6.25 through 2.6.28 might allow remote authenticated gateways to execute arbitr…EPSS 3.9%6.5CVE-2010-3308Xelerance openswan code injection vulnerabilityBuffer overflow in programs/pluto/xauth.c in the client in Openswan 2.6.26 through 2.6.28 might allow remote authenticated gateways to execute arbitr…EPSS 4.0%6.5CVE-2010-3752Xelerance openswan os command injection vulnerabilityprograms/pluto/xauth.c in the client in Openswan 2.6.25 through 2.6.28 allows remote authenticated gateways to execute arbitrary commands via shell m…EPSS 2.5%5.0CVE-2014-2037Xelerance openswan improper input validation vulnerabilityOpenswan 2.6.40 allows remote attackers to cause a denial of service (NULL pointer dereference and IKE daemon restart) via IKEv2 packets that lack ex…EPSS 2.4%

Source: NIST National Vulnerability Database (record CVE-2018-15836), CISA KEV, FIRST EPSS (scores of 2026-09-29). This page is refreshed as NVD updates the record.