CVE-2026-50722Network attack vector

Peer impersonation and daemon restart via malformed signatures

Published Jul 2, 2026 · Updated Jul 2, 2026

Improper signature verification in Libreswan 5.3 and earlier allows remote attackers to impersonate IKEv2 peers or restart the daemon. RSA_authenticate_hash_signature_pkcs1_1_5_rsa() accepts invalid DER encoding in an RSASSA-PKCS1-v1_5 AUTH digest and asserts on a digest shorter than expected. The impersonation path requires a small RSA public exponent such as e=3; malformed short hashes abort pluto, and repeated requests sustain the service interruption.

CVSS severity8.1
High
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper signature verification in Libreswan 5.3 and earlier allows remote attackers to impersonate IKEv2 peers or restart the daemon. RSA_authenticate_hash_signature_pkcs1_1_5_rsa() accepts invalid DER encoding in an RSASSA-PKCS1-v1_5 AUTH digest and asserts on a digest shorter than expected. The impersonation path requires a small RSA public exponent such as e=3; malformed short hashes abort pluto, and repeated requests sustain the service interruption.

The record

CVE
CVE-2026-50722
Published
Jul 2, 2026
Updated
Jul 2, 2026
Vendor
The Libreswan Project
Product
Libreswan
Classifications
CWE-617, CWE-347, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 2, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=5.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Libreswan Project · Libreswanversion=0 <=5.3

Published CVSS scores

8.1The Libreswan ProjectCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5OracleCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.9NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-617Reachable Assertion
CWE-347Improper Verification of Cryptographic Signature
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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