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CVE-2021-3695

MEDIUMCVSS 4.5/10EPSS 0.44%

Last modified

CVE-2021-3695 is a medium-severity vulnerability rated 4.5/10 on the CVSS scale. A crafted 16-bit grayscale PNG image may lead to a out-of-bounds write in the heap area. An attacker may take advantage of that to cause heap data corruption or eventually arbitrary code execution and circumvent secure boot protections. EPSS estimates a 0.44% chance of exploitation in the next 30 days.

Description

A crafted 16-bit grayscale PNG image may lead to a out-of-bounds write in the heap area. An attacker may take advantage of that to cause heap data corruption or eventually arbitrary code execution and circumvent secure boot protections. This issue has a high complexity to be exploited as an attacker needs to perform some triage over the heap layout to achieve signifcant results, also the values written into the memory are repeated three times in a row making difficult to produce valid payloads. This flaw affects grub2 versions prior grub-2.12.

Metrics

CVSS 3.1
4.5/10

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L

EPSS Probability
0.44%

35.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
GnuGrub2>= 2.00, < 2.12
FedoraprojectFedora36
RedhatDeveloper Tools1.0
RedhatOpenshift3.0
RedhatEnterprise Linux8.0
RedhatEnterprise Linux8.1
RedhatEnterprise Linux8.4
RedhatEnterprise Linux9.0
RedhatEnterprise Linux Eus8.2
RedhatEnterprise Linux Eus8.4
RedhatEnterprise Linux Eus8.6
RedhatEnterprise Linux Eus9.0
RedhatEnterprise Linux For Power Little Endian8.0
RedhatEnterprise Linux For Power Little Endian9.0
RedhatEnterprise Linux For Power Little Endian Eus8.2
RedhatEnterprise Linux For Power Little Endian Eus8.4
RedhatEnterprise Linux For Power Little Endian Eus8.6
RedhatEnterprise Linux For Power Little Endian Eus9.0
RedhatEnterprise Linux Server Aus8.2
RedhatEnterprise Linux Server Aus8.4
RedhatEnterprise Linux Server Aus8.6
RedhatEnterprise Linux Server For Power Little Endian Update Services For Sap Solutions8.1
RedhatEnterprise Linux Server For Power Little Endian Update Services For Sap Solutions8.2
RedhatEnterprise Linux Server For Power Little Endian Update Services For Sap Solutions8.4
RedhatEnterprise Linux Server For Power Little Endian Update Services For Sap Solutions8.6
RedhatEnterprise Linux Server For Power Little Endian Update Services For Sap Solutions9.0
RedhatEnterprise Linux Server Tus8.2
RedhatEnterprise Linux Server Tus8.4
RedhatEnterprise Linux Server Tus8.6
RedhatOpenshift Container Platform4.6
RedhatOpenshift Container Platform4.9
RedhatOpenshift Container Platform4.10
RedhatCodeready Linux BuilderAll versions
NetappOntap Select Deploy Administration UtilityAll versions

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2021-3695?
A crafted 16-bit grayscale PNG image may lead to a out-of-bounds write in the heap area. An attacker may take advantage of that to cause heap data corruption or eventually arbitrary code execution and circumvent secure boot protections. This issue has a high complexity to be exploited as an attacker needs to perform some triage over the heap layout to achieve signifcant results, also the values written into the memory are repeated three times in a row making difficult to produce valid payloads. This flaw affects grub2 versions prior grub-2.12.
How severe is CVE-2021-3695?
CVE-2021-3695 has a CVSS score of 4.5/10 (MEDIUM severity). The EPSS model estimates a 0.44% probability of exploitation in the next 30 days.
How do I fix CVE-2021-3695?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-3695?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST