CVE-2020-11091
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Weave Net clusters susceptible to MitM attacks via IPv6 rogue router advertisements
rank 17 = 0 + 15 + 0 + 2 + 0
rank@v1 · backlog
Someone is already using it
CISA KEV catalog · public proof-of-concept · FIRST EPSS
EPSS 0.00860 · without this subject the record ranks 17
What it costs you if it fires
NVD CVSS base score, then the CNA's own
CVSS 5.8, from NVD · without this subject the record ranks 2
It is getting worse, not staying still
FIRST EPSS series, rescorings and bad loads removed
no persisting rise in 365 days · without this subject the record ranks 17
How much of the world it touches
NVD CPE configurations
1 product in the CPE ranges · without this subject the record ranks 15
Someone else already set the date
CISA KEV remediation due date
no CISA due date · without this subject the record ranks 17
$26,300 = $4.99M incident cost x 0.6121449559255632 exposure x 0.0086 likelihood
udv@v1 · unaudited · wrong for you until you say what you run
$4.99M is the cost of a breach that happened, from IBM Cost of a Data Breach Report 2026, global average. It is not the value of any asset of yours. That average already covers breaches of every severity, so scaling it by exposure understates a partial-impact record. That is an assumption, not a measurement. Your own asset value goes in the decision record.
Hindsight · the state
Foresight · where to check next
No weakness class or product neighbourhood is held for this record, so this index cannot name anywhere to check next. That is an absence in the record, not a finding about the software.
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Harm, if it fires from the vector and the weakness
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CISA KEV & Federal Remediation Deadline from the record and CISA
The fix, and how long it's been waiting.
Exploit Status & Known PoCs a ladder, not a score
Current rung: Nothing observed in held sources.
- RUNG 1Nothing observed in held sources
- RUNG 2Proof-of-concept published
- RUNG 3Exploited in the wild · CISA KEV listed
- RUNG 4Ransomware campaign use known
A rung lights from a row in the index, never from an assessment. "Held sources" is the true scope of the claim: this index reads the CVE record, NVD, CISA KEV, FIRST's EPSS and public proof-of-concept repositories, and it does not observe attacks.
Attack path
What it is stated by the CNA
In Weave Net before version 2.6.3, an attacker able to run a process as root in a container is able to respond to DNS requests from the host and thereby insert themselves as a fake service. In a cluster with an IPv4 internal network, if IPv6 is not totally disabled on the host (via ipv6.disable=1 on the kernel cmdline), it will be either unconfigured or configured on some interfaces, but it's pretty likely that ipv6 forwarding is disabled, ie /proc/sys/net/ipv6/conf//forwarding == 0. Also by default, /proc/sys/net/ipv6/conf//accept_ra == 1. The combination of these 2 sysctls means that the host accepts router advertisements and configure the IPv6 stack using them. receipt
Read the rest of the CNA's description
By sending rogue router advertisements, an attacker can reconfigure the host to redirect part or all of the IPv6 traffic of the host to the attacker controlled container. Even if there was no IPv6 traffic before, if the DNS returns A (IPv4) and AAAA (IPv6) records, many HTTP libraries will try to connect via IPv6 first then fallback to IPv4, giving an opportunity to the attacker to respond. If by chance you also have on the host a vulnerability like last year's RCE in apt (CVE-2019-3462), you can now escalate to the host. Weave Net version 2.6.3 disables the accept_ra option on the veth devices that it creates.
NVD's analysis a second authority
- severity
- 5.8 CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:N/I:H/A:N
- weakness
- CWE-350
- affected versions
- weave net < 2.6.3
- also scored by
- [email protected] 5.8 CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:N/I:H/A:N
check it yourself github.com github.com receipt
Movement the material steps
Show all 12 observations
12 observations held. A highlighted step crossed a promotion threshold. A step marked with a scoring model moved because the instrument was replaced, not because the vulnerability changed. receipt
The full biography
The record had been public for 6 years when this index was last written.
Siblings and hubs
Records related to this one
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What usually comes next
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