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01 Record

CVE-2019-6477

TCP-pipelined queries can bypass tcp-clients limit

HighPUBLISHEDCNA: isc
CNA base score7.5 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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02 Description

TCP-pipelined queries can bypass tcp-clients limit

03 Exploitation and scoring

Exploitation
Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.
SSVC decision
Not assessed by CISA
EPSS probability
4.13% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 90.7% of scored records. A rank, not a probability.
NVD base score
7.5 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD analysis status
Modified. NVD last modified this record on 2026-06-17.
Red Hat severity
Moderate. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2019-11-26 16:11Z6 YR AGO
Last updated
2024-09-16 16:47Z2 YR AGO
Reserved
2019-01-16
Assigning CNA
isc
Record state
PUBLISHED
Severity
High (CVSS 7.5)
CNA CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weaknesses
  • CWE-400Uncontrolled Resource ConsumptionClass
Data version
5.1
Document digest
ceacd348f6ab61c5b32f45f49dfe9335cebecf97eaa6b89f79616ebd0a7c1521

05 Affected products

VendorProductVersionsPlatforms
ISCBIND99.11.6-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—

06 References

07 Remediation

Upgrade to the patched release most closely related to your current version of BIND: BIND 9.11.13 BIND 9.14.8 BIND 9.15.6 BIND Supported Preview Edition is a special feature preview branch of BIND provided to eligible ISC support customers. BIND 9.11.13-S1 Note that the fix for CVE-2019-6477 addresses only the server memory leak issue. TCP-pipelining may still malfunction by dropping some responses on a TCP connection where a client query pattern generates excessive outstanding queries, but the malfunction will affect that TCP connection alone and will not cause any degradation of service to other clients. An affected client connection might also appear to hang, but will clear when either the client or the server initiates a close or reset and will not remain in that state indefinitely. Disabling TCP-pipelining entirely is completely effective at mitigating the vulnerability with minimal impact to clients that use pipelined TCP connections and with no impact to clients that do not support TCP-pipelining. The majority of Internet client DNS queries are transported over UDP or TCP without use of TCP-pipelining.

08 Fixed in

Debian 12

  • bind9
    Fixed in 1:9.11.14+dfsg-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 13

  • bind9
    Fixed in 1:9.11.14+dfsg-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 14

  • bind9
    Fixed in 1:9.11.14+dfsg-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 18.04 LTS

  • bind9
    Fixed in 1:9.11.3+dfsg-1ubuntu1.11

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.