CVE-2024-21639 | OOB Access in CefLayeredWindowUpdaterOSR::OnAllocatedSharedMemory

Exp

CEF (Chromium Embedded Framework ) is a simple framework for embedding Chromium-based browsers in other applications. `CefLayeredWindowUpdaterOSR::OnAllocatedSharedMemory` does not check the size of the shared memory, which leads to out-of-bounds read outside the sandbox. This vulnerability was patched in commit 1f55d2e.

Published: 2024-01-12 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2024-21639 is rated Exploit Available (53.5/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.70%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

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

Public exploit references (Exploit-DB) for CVE-2024-21639

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2024-21639

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 2026-06-15 0.21% 0.70% +0.49%
2 2025-11-21 0.52% 0.21% -0.31%
3 2025-11-18 — 0.52% —

Full EPSS history (9 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2024-21639

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H 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:L)
A normal user session is enough; they don’t have to be admin.
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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.6 3.6 [email protected]
9.6 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:H 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:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
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:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.1 5.8 [email protected]

Weakness enumeration for CVE-2024-21639

Affected software / configurations for CVE-2024-21639

Vendor Product Version Raw CPE
chromiumembedded chromium_embedded_framework < 2024-01-05 cpe:2.3:a:chromiumembedded:chromium_embedded_framework:*:*:*:*:*:*:*:*

References for CVE-2024-21639

cvelogic Threat Intelligence