Vulnerability in HyperKit (CVE-2021-32846)
Summary
Vulnerability in HyperKit (CVE-2021-32846). Successful exploitation can lead to full system takeover. Exploitable via pci_vtsock_proc_tx.
Original description
The description as published by the source.
HyperKit is a toolkit for embedding hypervisor capabilities in an application. In versions 0.20210107, function pci_vtsock_proc_tx in virtio-sock can lead to to uninitialized memory use. In this situation, there is a check for the return value to be less or equal to VTSOCK_MAXSEGS, but that check is not sufficient because the function can return -1 if it finds an error it cannot recover from. Moreover, the negative return value will be used by iovec_pull in a while condition that can further lead to more corruption because the function is not designed to handle a negative iov_len. This issue may lead to a guest crashing the host causing a denial of service and, under certain circumstance, memory corruption. This issue is fixed in commit af5eba2360a7351c08dfd9767d9be863a50ebaba.
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2021-32846 has been found in HyperKit.
Attackers can target a specific entry point like pci_vtsock_proc_tx over the network to misuse the product.
Successful exploitation can lead to full system takeover.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "HyperKit CVE-2021-32846" on the vendor's site.
CVE-2021-32846 (HyperKit)
Attack vector: local / no user interaction
Attack surface: pci_vtsock_proc_tx / VTSOCK_MAXSEGS / iovec_pull / iov_len
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (unclassified) exists in HyperKit. Attackers reach the vulnerable code path via pci_vtsock_proc_tx.
Check the vendor advisory for the affected versions of HyperKit. Attack surface: pci_vtsock_proc_tx / VTSOCK_MAXSEGS / iovec_pull / iov_len.
Severity: ?. Successful exploitation can lead to full system takeover.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'HyperKit' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'HyperKit' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
HyperKitを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- advisory securitylab.github.com
- patch github.com
- patch github.com