Krill: Reusing a Nonce, Key Pair in Encryption
CVE-2026-109140 is a high-severity reusing a nonce, key pair in encryption vulnerability in Krill from NLnet Labs, with a CVSS 3.1 base score of 8.4 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 0.31% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Krill you run against the affected versions below, and install the vendor's latest release.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| NLnet Labs | Krill | Not specified in the record | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- LowPerformance or availability is reduced.
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L. Scored by CNA (nlnetlabs.nl).
Official description
The vulnerability is that Krill encrypts every login-session token with a nonce built from a counter that is reset to 0 on every Krill restart, so the same (key, nonce) pair is used again after each restart.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Reusing a Nonce, Key Pair in Encryption
Nonces should be used for the present occasion and only once.
How developers prevent this class of flaw
- Use techniques such as requiring incrementing, time based and/or challenge response to assure uniqueness of nonces.
More Reusing a Nonce, Key Pair in Encryption vulnerabilities (CWE-323)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
References
Other references
Other vulnerabilities in Krill
- 8.4 High severity
- 8.4 High severity
- 7.5 High severity
Recent Reusing a Nonce, Key Pair in Encryption vulnerabilities
- 8.2 High severity
- 7.4 High severity
- 7.4 High severity
- 7.4 High severity
- 7.1 High severity
- 9.1 Critical severity
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