Missing Authorization The advisory has been revoked - it doesn't affect any version of package kernel-headers (opens in a new tab)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-RHEL7-KERNELHEADERS-7973502
- published14 Sept 2024
- disclosed16 Aug 2021
Introduced: 16 Aug 2021
CVE-2021-3656 (opens in a new tab)Amendment
The Red Hat security team deemed this advisory irrelevant for RHEL:7.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-headers package and not the kernel-headers package as distributed by RHEL.
A flaw was found in the KVM's AMD code for supporting SVM nested virtualization. The flaw occurs when processing the VMCB (virtual machine control block) provided by the L1 guest to spawn/handle a nested guest (L2). Due to improper validation of the "virt_ext" field, this issue could allow a malicious L1 to disable both VMLOAD/VMSAVE intercepts and VLS (Virtual VMLOAD/VMSAVE) for the L2 guest. As a result, the L2 guest would be allowed to read/write physical pages of the host, resulting in a crash of the entire system, leak of sensitive data or potential guest-to-host escape.
References
- https://access.redhat.com/security/cve/CVE-2021-3656
- https://access.redhat.com/errata/RHSA-2021:3801
- https://bugzilla.redhat.com/show_bug.cgi?id=1983988
- https://git.kernel.org/pub/scm/virt/kvm/kvm.git/commit/?id=c7dfa4009965a9b2d7b329ee970eb8da0d32f0bc
- https://github.com/torvalds/linux/commit/c7dfa4009965a9b2d7b329ee970eb8da0d32f0bc
- https://www.openwall.com/lists/oss-security/2021/08/16/1