CVE-2026-25998VulnerabilityPublished 19 Feb 2026

CVE-2026-25998: strongswan strongMan · Reusing a Nonce, Key Pair in Encryption

Affects strongswan strongManSource CVE Database V5

Not known to be exploited · CVSS 8.7 High : upgrade to 0.2.0 soon.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 4.0 base score

8.7High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 28% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 0.2.0

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: High
Vulnerable system integrity: None
Vulnerable system availability: None
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: High: There is a total loss of confidentiality, resulting in all information within the Vulnerable System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 19 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade strongswan strongMan to 0.2.0.

Affected software

Product	Affected	Fixed in
strongswanstrongMan	Affected <0.2.0	Fixed in 0.2.0

AI-suggested

Organizations should upgrade strongMan to version 0.2.0 or later immediately to benefit from the fixed encryption scheme using AES-GCM-SIV with random nonces and per-value derived keys. They must perform the provided database migration to securely re-encrypt all stored credentials. Until the upgrade is applied, strict access controls should be enforced on the strongMan database to prevent unauthorized read access. Monitoring and auditing database access logs can help detect suspicious activity. Additionally, organizations should consider rotating all VPN credentials managed by strongMan after remediation to invalidate any potentially compromised keys. Network segmentation and encryption of database backups can further reduce exposure. Finally, reviewing and hardening the overall infrastructure security posture, including limiting administrative privileges and employing multi-factor authentication for management interfaces, will mitigate the risk of initial database compromise.

Description

strongMan is a management interface for strongSwan, an OpenSource IPsec-based VPN. When storing credentials in the database (private keys, EAP secrets), strongMan encrypts the corresponding database fields. So far it used AES in CTR mode with a global database key. Together with an initialization vector (IV), a key stream is generated to encrypt the data in the database fields. But because strongMan did not generate individual IVs, every database field was encrypted using the same key stream. An attacker that has access to the database can use this to recover the encrypted credentials. In particular, because certificates, which have to be considered public information, are also encrypted using the same mechanism, an attacker can directly recover a large chunk of the key stream, which allows them to decrypt basically all other secrets especially ECDSA private keys and EAP secrets, which are usually a lot shorter. Version 0.2.0 fixes the issue by switching to AES-GCM-SIV encryption with a random nonce and an individually derived encryption key, using HKDF, for each encrypted value. Database migrations are provided to automatically re-encrypt all credentials.

Impact

The vulnerability allows an attacker with read access to the strongMan database to decrypt all stored credentials, including private keys and EAP secrets. This compromises the confidentiality of VPN credentials, potentially enabling unauthorized access to VPN tunnels and sensitive network resources. Organizations relying on strongMan for managing strongSwan VPN credentials risk exposure of critical cryptographic material, which can lead to interception, impersonation, or man-in-the-middle attacks on VPN communications. The impact is particularly severe for enterprises and service providers using strongSwan for secure remote access or site-to-site VPNs, as it undermines the trustworthiness of their VPN infrastructure. Since exploitation requires database access, the vulnerability also highlights the importance of securing backend systems and databases. The breach of private keys can have long-term consequences, including the need to revoke and reissue certificates and reconfigure VPN endpoints, causing operational disruption and increased incident response costs.

CWE-323Reusing a Nonce, Key Pair in Encryption (opens in a new tab)
Base weaknessLikelihood of exploit: HighOWASP Top 10 A04:2025: Cryptographic Failures (opens in a new tab)
Nonces should be used for the present occasion and only once.
Implementation
Refuse to reuse nonce values.
Implementation
Use techniques such as requiring incrementing, time based and/or challenge response to assure uniqueness of nonces.
OWASP Cheat Sheets
Forgot Password (opens in a new tab)
Transport Layer Protection (opens in a new tab)
User Privacy Protection (opens in a new tab)
Password Storage (opens in a new tab)
Cryptographic Storage (opens in a new tab)
OWASP ASVS 4.0.3
V2.3.1 (opens in a new tab)
V2.6.2 (opens in a new tab)
V2.7.6 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-1204Generation of Weak Initialization Vector (IV) (opens in a new tab)
Base weakness
The product uses a cryptographic primitive that uses an Initialization Vector (IV), but the product does not generate IVs that are sufficiently unpredictable or unique according to the expected cryptographic requirements for that primitive.
Implementation
Different cipher modes have different requirements for their IVs. When choosing and implementing a mode, it is important to understand those requirements in order to keep security guarantees intact.
OWASP Cheat Sheets
Forgot Password (opens in a new tab)
OWASP ASVS 4.0.3
V2.3.1 (opens in a new tab)
V2.6.2 (opens in a new tab)
V2.7.6 (opens in a new tab)
Attack patterns
Encryption Brute Forcing (opens in a new tab)
Cryptanalysis (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

github.com/strongswan/strongMan/security/advisories/GHSA-88w4-jv97-c8xr (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 28 Feb 2026, 14:45 UTC

WeaknessesCWE-323, CWE-1204

Technical details

References

Community reviews

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