How severe is CVE-2021-34999?

CVE-2021-34999 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 high, integrity none, and availability none.

Is CVE-2021-34999 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-34999?

CVE-2021-34999 affects Openbsd. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-34999?

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

Does CVE-2021-34999 have an EU (EUVD) identifier?

Yes. CVE-2021-34999 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-21646.

When was CVE-2021-34999 published?

CVE-2021-34999 was published on 2024-05-07 and last updated on 2026-06-17.

CVE-2021-34999

CVE-2021-34999 is a medium-severity vulnerability in Openbsd 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-908.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
EPSS exploit prediction: 0% (15th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2021-21646
Weakness: CWE-908
Affected product: Openbsd
Published: 2024-05-07
Last modified: 2026-06-17

Description

OpenBSD Kernel Multicast Routing Uninitialized Memory Information Disclosure Vulnerability. This vulnerability allows local attackers to disclose sensitive information on affected installations of OpenBSD Kernel. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. The specific flaw exists within the implementation of multicast routing. The issue results from the lack of proper initialization of memory prior to accessing it. An attacker can leverage this in conjunction with other vulnerabilities to escalate privileges and execute arbitrary code in the context of the kernel. . Was ZDI-CAN-14540.

Frequently asked questions

What is CVE-2021-34999?: OpenBSD Kernel Multicast Routing Uninitialized Memory Information Disclosure Vulnerability. This vulnerability allows local attackers to disclose sensitive information on affected installations of OpenBSD Kernel. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. The specific flaw exists within the implementation of multicast routing. The issue results from the lack of proper initialization of memory prior to accessing it. An attacker can leverage this in conjunction with other vulnerabilities to escalate privileges and execute arbitrary code in the context of the kernel. . Was ZDI-CAN-14540.
How severe is CVE-2021-34999?: CVE-2021-34999 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 high, integrity none, and availability none.
Is CVE-2021-34999 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (15th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-34999?: CVE-2021-34999 affects Openbsd. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-34999?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2021-34999 have an EU (EUVD) identifier?: Yes. CVE-2021-34999 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-21646.
When was CVE-2021-34999 published?: CVE-2021-34999 was published on 2024-05-07 and last updated on 2026-06-17.

References

https://www.zerodayinitiative.com/advisories/ZDI-22-073/

Affected products (1)

cpe:2.3:o:openbsd:openbsd:6.9:*:*:*:*:*:*:*

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