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CVE-2018-15836

24
FAUCET Score

CVE-2018-15836 is a high-severity vulnerability affecting Openswan before version 2.6.50.1, specifically in the verify_signed_hash() function. It allows a remote attacker to forge IKEv2 signatures when RAW RSA keys and small public exponents are used, due to improper padding string verification during PKCS#1 v1.5 signature verification. The vulnerability has a CVSS score of 7.5, indicating a high impact on integrity with low attack complexity and no user interaction required. Despite its severity, there is no known active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
< 2.6.50.1CPE matchmatch criteria
cpe:2.3:a:xelerance:openswan:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

7.5HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
HIGH
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.0

Exploit Intelligence

EPSS Score
1.52%
Probability of exploitation in next 30 days
EPSS Percentile
72.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.0152 is in the 54th percentile among its peer group of 51,485 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

github_advisorypatch availablevia nvd_reference
View patch

Vendor Advisories (1)

redhatCVE-2018-15836Moderate

openswan: Improper signature verification in try_RSA_signature_v2() fucntion for RSASSA-PKCS1-v1_5 signature scheme

Aug 17, 2018

References

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