CVE-2021-35000

Kernel-memory disclosure via uninitialized multicast routing data

Published May 7, 2024 · Updated Sep 18, 2024

Information disclosure in OpenBSD Kernel 6.9 allows local users to read sensitive memory through the multicast-routing implementation. The multicast-routing implementation accesses memory before initializing it, exposing residual kernel data to a caller. Low-privileged code execution on the host is required; the disclosure alone does not change data or interrupt service.

CVSS severity3.3
Low
EPSS probability0.25%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in OpenBSD Kernel 6.9 allows local users to read sensitive memory through the multicast-routing implementation. The multicast-routing implementation accesses memory before initializing it, exposing residual kernel data to a caller. Low-privileged code execution on the host is required; the disclosure alone does not change data or interrupt service.

The record

CVE
CVE-2021-35000
Published
May 7, 2024
Updated
Sep 18, 2024
Vendor
OpenBSD Project
Product
OpenBSD Kernel
Classifications
CWE-908, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 7, 2024CVE publishedPublication date reported by the CVE source.
  2. Sep 18, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=OpenBSD 6.9

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

OpenBSD Project · OpenBSD Kernelversion=OpenBSD 6.9

Published CVSS scores

3.3Zero Day InitiativeCVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-908Use of Uninitialized Resource
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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