How severe is CVE-2026-21991?

CVE-2026-21991 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-21991 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-21991?

CVE-2026-21991 primarily affects Oracle Linux. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-21991?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-21991 have an EU (EUVD) identifier?

Yes. CVE-2026-21991 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-12522.

When was CVE-2026-21991 published?

CVE-2026-21991 was published on 2026-03-16 and last updated on 2026-06-17.

CVE-2026-21991

CVE-2026-21991 is a medium-severity vulnerability in Oracle Linux with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-22.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
EPSS exploit prediction: 0% (8th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-12522
Weakness: CWE-22
Affected product: Oracle Linux
Published: 2026-03-16
Last modified: 2026-06-17

Description

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

Frequently asked questions

What is CVE-2026-21991?: A DTrace component, dtprobed, allows arbitrary file creation through crafted USDT provider names.
How severe is CVE-2026-21991?: CVE-2026-21991 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-21991 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-21991?: CVE-2026-21991 primarily affects Oracle Linux. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-21991?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-21991 have an EU (EUVD) identifier?: Yes. CVE-2026-21991 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-12522.
When was CVE-2026-21991 published?: CVE-2026-21991 was published on 2026-03-16 and last updated on 2026-06-17.

References

https://linux.oracle.com/cve/CVE-2026-21991.html

Affected products (3)

cpe:2.3:o:oracle:linux:8:-:*:*:*:*:*:*
cpe:2.3:o:oracle:linux:9:0:*:*:*:*:*:*
cpe:2.3:o:oracle:linux:10:0:*:*:*:*:*:*

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