VulnerabilityPublished 30 May 2025

CVE-2025-48946: open-quantum-safe liboqs · Weak Cryptography

Affects open-quantum-safe liboqsSource CVE Database V5

Not known to be exploited · CVSS 3.7 Low : upgrade to 0.13.0 when convenient.

Data as of 26 Oct 2026, 12:55 UTC

CVSS 3.1 base score

3.7Low

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 14% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 0.13.0

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Attack Vector: Network
Attack Complexity: High
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: None
Availability: None

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

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, 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: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 30 May 2025
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 26 Oct 2026.

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 or the CVSS exploit maturity 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 open-quantum-safe/liboqs to 0.13.0.

Affected software

Product	Affected	Fixed in
GitHubopen-quantum-safe/liboqs`pkg:github/open-quantum-safe/liboqs`Other threats	Affected <0.13.0	Fixed in 0.13.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

European organizations should take the following specific actions: 1) Immediately audit their cryptographic libraries and protocols to identify any use of liboqs versions prior to 0.13.0 and check if the HQC algorithm is enabled. 2) Disable the HQC algorithm in all deployments until a secure update or revised algorithm specification is released by the HQC team. 3) Prefer alternative post-quantum algorithms with stronger security guarantees such as Kyber or ML-KEM, which are supported by liboqs and do not exhibit this flaw. 5) For organizations developing custom protocols, conduct thorough cryptographic reviews to avoid relying on HQC for key derivation or other critical operations. 6) Engage with cryptographic experts to assess the impact of this vulnerability on ongoing quantum-safe initiatives and adjust risk management accordingly. 7) Incorporate this vulnerability into supply chain risk assessments, ensuring third-party vendors are not using vulnerable versions of liboqs with HQC enabled.

Description

liboqs is a C-language cryptographic library that provides implementations of post-quantum cryptography algorithms.liboqs prior to version 0.13.0 supports the HQC algorithm, an algorithm with a theoretical design flaw which leads to large numbers of malformed ciphertexts sharing the same implicit rejection value. Currently, no concrete attack on the algorithm is known. However, prospective users of HQC must take extra care when using the algorithm in protocols involving key derivation. In particular, HQC does not provide the same security guarantees as Kyber or ML-KEM. OQS will update its implementation after the HQC team releases an updated algorithm specification.

Impact

For European organizations, the impact of this vulnerability is currently limited but should not be ignored. Organizations experimenting with or deploying post-quantum cryptography solutions using liboqs versions prior to 0.13.0 and specifically enabling the HQC algorithm may face risks related to weakened cryptographic assurances. This could potentially lead to subtle cryptographic failures or reduced resistance to future cryptanalysis, undermining the confidentiality of sensitive communications or key material. However, since no active exploits or practical attacks are known, immediate risk is low. The main concern is for organizations involved in research, development, or early adoption of post-quantum cryptographic protocols, such as governmental agencies, financial institutions, and critical infrastructure operators who prioritize quantum-resistant security. The flaw could delay the secure deployment of post-quantum cryptography, impacting long-term cryptographic agility strategies. Given the growing interest in quantum-safe cryptography in Europe, especially within the EU's cybersecurity initiatives, this vulnerability highlights the importance of cautious algorithm selection and staying current with library updates.

CWE-327Use of a Broken or Risky Cryptographic Algorithm (opens in a new tab)
Class weaknessLikelihood of exploit: HighOWASP Top 10 A04:2025: Cryptographic Failures (opens in a new tab)
The product uses a broken or risky cryptographic algorithm or protocol.
Architecture and Design · Libraries or Frameworks
When there is a need to store or transmit sensitive data, use strong, up-to-date cryptographic algorithms to encrypt that data. Select a well-vetted algorithm that is currently considered to be strong by experts in the field, and use well-tested implementations.
Architecture and Design
Ensure that the design allows one cryptographic algorithm to be replaced with another in the next generation or version. Where possible, use wrappers to make the interfaces uniform. This will make it easier to upgrade to stronger algorithms.
Architecture and Design
Carefully manage and protect cryptographic keys (see CWE-320). If the keys can be guessed or stolen, then the strength of the cryptography itself is irrelevant.
OWASP Cheat Sheets
Cryptographic Storage (opens in a new tab)
Key Management (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)
OWASP ASVS 4.0.3
V8.3.7 (opens in a new tab)
V2.9.3 (opens in a new tab)
V6.2.2 (opens in a new tab)
Attack patterns
Encryption Brute Forcing (opens in a new tab)
Creating a Rogue Certification Authority Certificate (opens in a new tab)
Signature Spoof (opens in a new tab)
Signature Spoofing by Improper Validation (opens in a new tab)
Cryptanalysis of Cellular Encryption (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 8 Jul 2025, 13:43 UTC

WeaknessesCWE-327

Technical details

References

Community reviews

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