What’s Vulnerable › Vulnerabilities
CVE-2021-3695
- Severity: medium (CVSS 4.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.5% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2022-07-06 · updated 2026-06-17
- Weakness: CWE-787
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.
Affected products
- Fedoraproject Fedora: 36
- grub2: from 2.00 before 2.12 — fixed in 2.12
- NetApp ONTAP Select Deploy administration utility: all versions
- RedHat Codeready Linux Builder: all versions
- RedHat Developer Tools: 1.0
- Red Hat Enterprise Linux: 8.0, 8.1, 8.4, 9.0
- RedHat Enterprise Linux Eus: 8.2, 8.4, 8.6, 9.0
- RedHat Enterprise Linux For Power Little Endian: 8.0, 9.0
- RedHat Enterprise Linux For Power Little Endian Eus: 8.2, 8.4, 8.6, 9.0
- RedHat Enterprise Linux Server Aus: 8.2, 8.4, 8.6
- RedHat Enterprise Linux Server For Power Little Endian Update Services For Sap Solutions: 8.1, 8.2, 8.4, 8.6, 9.0
- RedHat Enterprise Linux Server Tus: 8.2, 8.4, 8.6
- Openshift: 3.0
- Red Hat OpenShift Container Platform 4.18: 4.6, 4.9, 4.10
How to fix
Upgrade to a fixed version: grub2 2.12. Check the vendor advisory for mitigations.
References
- https://bugzilla.redhat.com/show_bug.cgi?id=1991685
- https://security.gentoo.org/glsa/202209-12
- https://security.netapp.com/advisory/ntap-20220930-0001/
- https://bugzilla.redhat.com/show_bug.cgi?id=1991685
- https://security.gentoo.org/glsa/202209-12
- https://security.netapp.com/advisory/ntap-20220930-0001/
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