CVE-2021-38203

Exp

btrfs in the Linux kernel before 5.13.4 allows attackers to cause a denial of service (deadlock) via processes that trigger allocation of new system chunks during times when there is a shortage of free space in the system space_info.

Published: 2021-08-08 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-38203 is rated Exploit Available (50/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.05%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2021-38203

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-38203

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-07-30 0.04% 0.05% +0.01%
2 2025-03-30 0.15% 0.04% -0.10%
3 2025-03-29 — 0.15% —

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-38203

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 3.6 [email protected]
2.1 2.0 LOW
AV:L/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 3.9 2.9 [email protected]

Weakness enumeration for CVE-2021-38203

OS Trackers for CVE-2021-38203

vendor priority summary link
debian unimportant CVE-2021-38203 unimportant priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-38203
redhat medium — https://access.redhat.com/security/cve/CVE-2021-38203
ubuntu medium CVE-2021-38203 medium priority: Ubuntu including 123 source packages (linux, linux-allwinner, …), 1326 status rows across 12 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, trusty, upstream, xenial): DNE 977, not-affected 195, released 103, ignored 51. https://ubuntu.com/security/CVE-2021-38203

Affected software / configurations for CVE-2021-38203

Vendor Product Version Raw CPE
linux linux_kernel < 5.13.4 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
netapp hci_bootstrap_os — cpe:2.3:o:netapp:hci_bootstrap_os:-:*:*:*:*:*:*:*
netapp hci_management_node — cpe:2.3:a:netapp:hci_management_node:-:*:*:*:*:*:*:*
netapp solidfire — cpe:2.3:a:netapp:solidfire:-:*:*:*:*:*:*:*
netapp element_software — cpe:2.3:a:netapp:element_software:-:*:*:*:*:*:*:*

References for CVE-2021-38203

cvelogic Threat Intelligence