Skip to content
Fencer Vulns
medium 5.9

CVE-2025-52473 json

liboqs secret-dependent branching in HQC reference implementation when compiled with Clang 17-20

published 2025-07-10 15 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-21027

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 14%
public exploits
0
none known

Summary

liboqs is a C-language cryptographic library that provides implementations of post-quantum cryptography algorithms. Multiple secret-dependent branches have been identified in the reference implementation of the HQC key encapsulation mechanism when it is compiled with Clang for optimization levels above -O0 (-O1, -O2, etc). A proof-of-concept local attack exploits this secret-dependent information to recover the entire secret key. This vulnerability is fixed in 0.14.0.

Patch / fix

  • openquantumsafe liboqs 0.14.0
  • liboqs SLES for SAP applications 16.0, SLES 16.0 0.16.0-160000.1.1
  • oqs-provider SLES for SAP applications 16.0, SLES 16.0 0.11.0.32-160000.1.1
  • oqs-provider SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Basesystem 15 SP7 0.11.0.32-150600.3.9.1
  • liboqs SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Basesystem 15 SP7 0.16.0-150600.3.6.1

suse advisories SUSE-SU-2026:23313-1SUSE-SU-2026:3420-1

  • liboqs openSUSE Leap 16.0 0.16.0-160000.1.1
  • oqs-provider openSUSE Leap 16.0 0.11.0.32-160000.1.1
  • liboqs openSUSE Tumbleweed 0.14.0-1.1

opensuse advisories openSUSE-SU-2026:21634-1openSUSE-SU-2025:15339-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-52473 updated cvss 5.9

liboqs: liboqs secret-dependent branching in HQC

  • Red Hat Enterprise Linux 10 liboqs
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
15 mo ago

Exploit prediction

0.24% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Affected products

  • open-quantum-safe liboqs

Classification

Weakness
  • CWE-200 Exposure of Sensitive Information to an Unauthorized Actor

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.