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Fencer Vulns
medium 5.3

CVE-2024-21639 json

OOB Access in CefLayeredWindowUpdaterOSR::OnAllocatedSharedMemory

published 2024-01-12 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-19277

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 53%
public exploits
0
none known

Summary

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.

Patch / fix

  • chromiumembedded chromium_embedded_framework 2024-01-05

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.70% chance of exploitation in the next 30 days, higher than 53% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/chromiumembedded/cef/security/advisories/GHSA-m375-jw5x-x8mg referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 9.6 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:H

Affected products

  • chromiumembedded cef
  • chromiumembedded chromium_embedded_framework

Classification

Weakness

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.