HOMEVULNERABILITIESCVE-2018-15836
HIGH

CVE-2018-15836

CWE-347Published: September 26, 2018· Updated: Jun 17, 2026

7.5
CVSS v3.1

Official 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.

NVD Source

Technical Analysis

CVE-2018-15836 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in full integrity compromise (data manipulation), with a CVSS base score of 7.5.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityHigh
AvailabilityNone
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected Vendors & Products

xelerance1 product(s)
openswan
Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

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

All References (6)

→
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

Quick Facts

CVE IDCVE-2018-15836
CVSS Score7.5 / 10
SeverityHIGH
WeaknessCWE-347
CISA KEVNo
Affected1 vendor(s)
PublishedSep 26, 2018

Related CVEs (CWE-347)

CVE-2024-32962
10.0
CVE-2026-48558
KEV10.0
CVE-2026-56451
10.0
CVE-2026-44748
9.9
CVE-2025-8454
9.8
CVE-2023-28801
9.8

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2018-15836 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
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