CVE-2024-36405 | Control-flow timing leak in Kyber reference implementation when compiled with Clang 15-18 for -Os, -O1 and other options

liboqs is a C-language cryptographic library that provides implementations of post-quantum cryptography algorithms. A control-flow timing lean has been identified in the reference implementation of the Kyber key encapsulation mechanism when it is compiled with Clang 15-18 for `-Os`, `-O1`, and other compilation options. A proof-of-concept local attack on the reference implementation leaks the entire ML-KEM 512 secret key in ~10 minutes using end-to-end decapsulation timing measurements. The issue has been fixed in version 0.10.1. As a possible workaround, some compiler options may produce vectorized code that does not leak secret information, however relying on these compiler options as a workaround may not be reliable.

Published: 2024-06-10 Last update: 2025-08-20 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2024-36405 is rated Moderate Risk (45.5/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.45%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2024-36405

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-11-21 0.57% 0.45% -0.12%
2 2025-11-18 0.45% 0.57% +0.12%
3 2025-10-30 — 0.45% —

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2024-36405

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.9 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 3.6 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2024-36405

OS Trackers for CVE-2024-36405

vendor priority summary link
redhat medium — https://access.redhat.com/security/cve/CVE-2024-36405
suse medium CVE-2024-36405 severity moderate: SUSE including 9 source package names (liboqs-devel-0.10.1-1.1, liboqs-devel-0.12.0-150600.3.3.1, …), 17 product×package rows across 6 product lines (SUSE Linux Enterprise Module for Basesystem 15 SP6, SUSE Linux Enterprise Module for Basesystem 15 SP7, … (6 product lines)): Fixed 17. https://www.suse.com/security/cve/CVE-2024-36405/

Affected software / configurations for CVE-2024-36405

Vendor Product Version Raw CPE
openquantumsafe liboqs < 0.10.1 cpe:2.3:a:openquantumsafe:liboqs:*:*:*:*:*:*:*:*

References for CVE-2024-36405

cvelogic Threat Intelligence