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CVE-2019-6477

26
FAUCET Score

CVE-2019-6477 describes a resource exhaustion vulnerability in ISC BIND and Fedora Project's BIND implementations. When TCP pipelining is enabled, a malicious client can send numerous pipelined queries, causing the server to allocate excessive resources, and upon connection closure, the server can become unresponsive due to the load of releasing these resources. This vulnerability has a CVSS score of 7.5 (High), indicating it can be exploited remotely with low complexity to achieve high availability impact. There is no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
>= 9.11.7, <= 9.11.12CPE matchmatch criteria
cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*
>= 9.14.1, <= 9.14.7CPE matchmatch criteria
cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*
>= 9.15.0, <= 9.15.5CPE matchmatch criteria
cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*
9.11.5CPE matchmatch criteria
cpe:2.3:a:isc:bind:9.11.5:s6:*:*:supported_preview:*:*:*
9.11.6CPE matchmatch criteria
cpe:2.3:a:isc:bind:9.11.6:p1:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.5HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
4.06%
Probability of exploitation in next 30 days
EPSS Percentile
89.6%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0406 is in the 82nd percentile among its peer group of 51,553 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: bind-32:9.11.4-16.P2.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: bind-32:9.11.13-3.el8
View patch

Vendor Advisories (1)

redhatCVE-2019-6477Moderate

bind: TCP Pipelining doesn't limit TCP clients on a single connection

Nov 20, 2019

References

lists.opensuse.org / opensuse-security-announce/2020-10/msg00041.html
lists.opensuse.org / opensuse-security-announce/2020-10/msg00044.html
kb.isc.org / docs/cve-2019-6477
Third Party Advisory
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/L3DEMNZMKR57VQJCG5ZN55ZGTQRL2TFQ
lists.fedoraproject.org / archives/list/package-announce%40lists.fedoraproject.org/message/XGURMGQHX45KR4QDRCSUQHODUFOGNGAN
support.f5.com / csp/article/K15840535
debian.org / security/2020/dsa-4689
synology.com / security/advisory/Synology_SA_19_39
Third Party Advisory