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CVE-2021-3631
A flaw was found in libvirt while it generates SELinux MCS category pairs for VMs' dynamic labels. This flaw allows one exploited guest to…
Medium6.3EPSS 0.49%
- Published
- Updated
- Reserved
- Assigned by
- redhat
Description
A flaw was found in libvirt while it generates SELinux MCS category pairs for VMs' dynamic labels. This flaw allows one exploited guest to access files labeled for another guest, resulting in the breaking out of sVirt confinement. The highest threat from this vulnerability is to confidentiality and integrity.
Timeline
ID reserved
By redhat
- 8 months later
· 8 months later
Published
- 3 years later
· 3 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | Medium6.3 | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N |
- EPSS (exploitation in 30 days)
- 0.49% · top 57% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: total
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.3.
Weakness
Affected products
libvirt
- affected Fixed-In - libvirt v7.5.0
References (7)
- https://bugzilla.redhat.com/show_bug.cgi?id=1977726 (opens in a new tab)x_transferred
- https://gitlab.com/libvirt/libvirt/-/issues/153 (opens in a new tab)x_transferred
- https://gitlab.com/libvirt/libvirt/-/commit/15073504dbb624d3f6c911e85557019d3620fdb2 (opens in a new tab)x_transferred
- https://access.redhat.com/errata/RHSA-2021:3631 (opens in a new tab)x_transferred
- https://security.netapp.com/advisory/ntap-20220331-0010/ (opens in a new tab)x_transferred
- GLSA-202210-06 (opens in a new tab)vendor-advisoryx_transferred
- [debian-lts-announce] 20240401 [SECURITY] [DLA 3778-1] libvirt security update (opens in a new tab)mailing-listx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2021-3631)Record last updated .