What is CVE-2024-21639?

CVE-2024-21639 is a medium-severity vulnerability in Chromiumembedded Cef, classified under Out-of-bounds Read. CVSS score: 5.3/10. Published 2024-01-12.

How severe is CVE-2024-21639?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Out-of-bounds Read in Chromiumembedded Cef

CVE-2024-21639

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.

Vulnerability class: Buffer Overflow

Published 2024-01-12 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.007 (51.4th percentile), scored 2026-10-02.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 51st percentile — 51.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Chromiumembedded Cef — versions < commit 1f55d2e
Chromiumembedded Chromium Embedded Framework

Weakness classification (CWE)

CWE-125 — Out-of-bounds Read

References

github.com/chromiumembedded/cef/security/advisories/GHSA-m375-jw5x-x8mg (Exploit, Vendor Advisory)
github.com/chromiumembedded/cef/commit/1f55d2e12f62cfdfbf9da6968fde2f928982670b (Patch)

Frequently asked questions

What is CVE-2024-21639?: CVE-2024-21639 is a medium-severity vulnerability in Chromiumembedded Cef, classified under Out-of-bounds Read. CVSS score: 5.3/10. Published 2024-01-12.
How severe is CVE-2024-21639?: Medium severity. CVSS v3 base score is 5.3 out of 10.