Vulnerability Details : CVE-2021-20321
A race condition accessing file object in the Linux kernel OverlayFS subsystem was found in the way users do rename in specific way with OverlayFS. A local user could use this flaw to crash the system.
Products affected by CVE-2021-20321
- cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
- cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
- cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
- cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:5.15:-:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:5.15:rc1:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:5.15:rc2:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:5.15:rc3:*:*:*:*:*:*
- cpe:2.3:o:linux:linux_kernel:5.15:rc4:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2021-20321
0.04%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 6 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2021-20321
Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
---|---|---|---|---|---|---|
4.7
|
MEDIUM | AV:L/AC:M/Au:N/C:N/I:N/A:C |
3.4
|
6.9
|
NIST | |
4.7
|
MEDIUM | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H |
1.0
|
3.6
|
NIST |
CWE ids for CVE-2021-20321
-
The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.Assigned by:
- nvd@nist.gov (Primary)
- secalert@redhat.com (Secondary)
References for CVE-2021-20321
-
https://www.debian.org/security/2022/dsa-5096
Debian -- Security Information -- DSA-5096-1 linuxThird Party Advisory
-
https://lists.debian.org/debian-lts-announce/2022/03/msg00012.html
[SECURITY] [DLA 2941-1] linux-4.19 security updateMailing List;Third Party Advisory
-
https://lore.kernel.org/all/20211011134508.748956131@linuxfoundation.org/
[PATCH 5.10 11/83] ovl: fix missing negative dentry check in ovl_rename() - Greg Kroah-HartmanPatch;Vendor Advisory
-
https://bugzilla.redhat.com/show_bug.cgi?id=2013242
2013242 – (CVE-2021-20321) CVE-2021-20321 kernel: In Overlayfs missing a check for a negative dentry before calling vfs_rename()Issue Tracking;Third Party Advisory
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