Resource exhaustion in Isc Bind

CVE-2019-6477

With pipelining enabled each incoming query on a TCP connection requires a similar resource allocation to a query received via UDP or via TCP without pipelining enabled. A client using a TCP-pipelined connection to a server could consume more resources than the server has been provisioned to handle. When a TCP connection with a large number of pipelined queries is closed, the load on the server releasing these multiple resources can cause it to become unresponsive, even for queries that can be answered authoritatively or from cache. (This is most likely to be perceived as an intermittent server problem).

Vulnerability class: DoS (Denial of Service)

EPSS: 0.041 (90.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

  • Isc Bind — versions 9.11.5, 9.11.6, 9.11.12
  • Isc Bind9 — versions 9.11.6-P1 -> 9.11.12, 9.12.4-P1 -> 9.12.4-P2, 9.14.1 -> 9.14.7, and versions 9.11.5-S6 -> 9.11.12-S1 of BIND 9 Supported Preview Edition. Versions 9.15.0 -> 9.15.5 of the BIND 9.15 development branch are also affected
  • Fedoraproject Fedora — versions 30, 31

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2019-6477?
CVE-2019-6477 is a high-severity vulnerability in Isc Bind, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2019-11-26.
How severe is CVE-2019-6477?
High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2019-6477 known to be exploited?
8 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.