CVE-2025-52473

Secret-key recovery via HQC secret-dependent branches

Published Jul 10, 2025 · Updated Jul 10, 2025

Timing side channel in liboqs before 0.14.0 allows attackers to recover HQC secret keys through optimized Clang builds. Clang 17 through 20 introduces secret-dependent branches into the HQC reference implementation when optimization above -O0 is enabled. A local proof of concept measures this control-flow leakage to recover the entire secret key; integrity and availability are unaffected.

CVSS severity5.9
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Timing side channel in liboqs before 0.14.0 allows attackers to recover HQC secret keys through optimized Clang builds. Clang 17 through 20 introduces secret-dependent branches into the HQC reference implementation when optimization above -O0 is enabled. A local proof of concept measures this control-flow leakage to recover the entire secret key; integrity and availability are unaffected.

The record

CVE
CVE-2025-52473
Published
Jul 10, 2025
Updated
Jul 10, 2025
Vendor
Open Quantum Safe
Product
liboqs
Classifications
CWE-200
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Jul 10, 2025CVE publishedPublication date reported by the CVE source.
  2. Jul 10, 2025Record 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=< 0.14.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

Open Quantum Safe · liboqsversion=< 0.14.0

Published CVSS scores

5.9GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

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.

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No observations available

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

Weakness, pattern, technique

CWE-200Exposure of Sensitive Information to an Unauthorized Actor

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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