Highly exploitable, CVE-2020-26278 poses a critical security risk that could lead to severe breaches.
Status: Analyzed
Last updated: 🕒 02 Feb 2021, 15:26 UTC
Originally published on: 🕙 20 Jan 2021, 22:15 UTC
Time between publication and last update: 12 days
CVSS Release: version 3
nvd@nist.gov
Primary
CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
CVE-2020-26278: Weave Net is open source software which creates a virtual network that connects Docker containers across multiple hosts and enables their automatic discovery. Weave Net before version 2.8.0 has a vulnerability in which can allow an attacker to take over any host in the cluster. Weave Net is supplied with a manifest that runs pods on every node in a Kubernetes cluster, which are responsible for managing network connections for all other pods in the cluster. This requires a lot of power over the host, and the manifest sets `privileged: true`, which gives it that power. It also set `hostPID: true`, which gave it the ability to access all other processes on the host, and write anywhere in the root filesystem of the host. This setting was not necessary, and is being removed. You are only vulnerable if you have an additional vulnerability (e.g. a bug in Kubernetes) or misconfiguration that allows an attacker to run code inside the Weave Net pod, No such bug is known at the time of release, and there are no known instances of this being exploited. Weave Net 2.8.0 removes the hostPID setting and moves CNI plugin install to an init container. Users who do not update to 2.8.0 can edit the hostPID line in their existing DaemonSet manifest to say false instead of true, arrange some other way to install CNI plugins (e.g. Ansible) and remove those mounts from the DaemonSet manifest.
The exploitability of CVE-2020-26278 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
This vulnerability, CVE-2020-26278, requires a high level of attack complexity and low privileges, making it difficult but not impossible to exploit. Organizations should ensure robust security configurations to mitigate risks.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2020-26278, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2020-26278, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
The EPSS score estimates the probability that this vulnerability will be exploited in the near future.
EPSS Score: 0.042% (probability of exploit)
EPSS Percentile: 5.02%
(lower percentile = lower relative risk)
This vulnerability is less risky than approximately 94.98% of others.
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