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Fencer Vulns
medium 6.8

CVE-2021-26928 json

BIRD through 2.0.7 does not provide functionality for password authentication of BGP peers.

published 2021-06-04 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-13710

cvss
6.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 63%
public exploits
0
none known

Summary

BIRD through 2.0.7 does not provide functionality for password authentication of BGP peers. Because of this, products that use BIRD (which may, for example, include Tigera products in some configurations, as well as products of other vendors) may have been susceptible to route redirection for Denial of Service and/or Information Disclosure. NOTE: a researcher has asserted that the behavior is within Tigera’s area of responsibility; however, Tigera disagrees

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-26928 updated cvss 7.4

bird: does not provide functionality for password authentication of BGP peers

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

1.01% chance of exploitation in the next 30 days, higher than 63% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • cyberark.com https://www.cyberark.com/resources/threat-research-blog/attacking-kubernetes-clusters-through-your-network-plumbing-part-2 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 6.8 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:H
NVD 3.1 6.8 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:H
CNA 3.1 6.8 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:H
NVD 2.0 4.9 AV:N/AC:M/Au:S/C:P/I:N/A:P

Affected products

  • nic bird

Classification

Weakness
  • CWE-306 Missing Authentication for Critical Functionality

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.