CVE-2026-21991

A DTrace component, dtprobed, allows arbitrary file creation through crafted USDT provider names.

Published: 2026-03-16 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-21991 is rated Low Risk (24.9/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.18%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

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

Exploit prediction scoring system (EPSS) score for CVE-2026-21991

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 2026-06-15 0.01% 0.18% +0.17%
2 2026-03-17 — 0.01% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-21991

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]
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]

Weakness enumeration for CVE-2026-21991

OS Trackers for CVE-2026-21991

vendor priority summary link
debian not yet assigned CVE-2026-21991 not yet assigned priority: Debian including 1 source packages (dtrace), 1 status rows across 1 suites (sid): resolved 1. https://security-tracker.debian.org/tracker/CVE-2026-21991
gentoo normal CVE-2026-21991: 1 GLSA(s) (202604-04), 1 atom(s) (dev-debug/dtrace); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2026-21991
ubuntu medium CVE-2026-21991 medium priority: Ubuntu including 1 source packages (dtrace), 4 status rows across 4 suites (jammy, noble, questing, upstream): DNE 3, released 1. https://ubuntu.com/security/CVE-2026-21991

Affected software / configurations for CVE-2026-21991

Vendor Product Version Raw CPE
oracle linux 8 cpe:2.3:o:oracle:linux:8:-:*:*:*:*:*:*
oracle linux 9 cpe:2.3:o:oracle:linux:9:0:*:*:*:*:*:*
oracle linux 10 cpe:2.3:o:oracle:linux:10:0:*:*:*:*:*:*

References for CVE-2026-21991

cvelogic Threat Intelligence