CVE-2019-20637

mediumpriority · track · 31EPSS 0.018 · 78 %ileDEEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

1.79% (78th) EPSS

CVSS 5 · medium

Is it mine?

41 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · cert_bund · nvd

EPSS · scored 2026-10-27

An issue was discovered in Varnish Cache before 6.0.5 LTS, 6.1.x and 6.2.x before 6.2.2, and 6.3.x before 6.3.1. It does not clear a pointer between the handling of one client request and the next request within the same connection. This sometimes causes information to be disclosed from the connection workspace, such as data structures associated with previous requests within this connection or VCL-related temporary headers.

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

Fixedvarnish-0:6.0.6-2.module+el8.3.0+6843+b3b42fcc.aarch64 (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-0:6.0.6-2.module+el8.3.0+6843+b3b42fcc.ppc64le (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-0:6.0.6-2.module+el8.3.0+6843+b3b42fcc.s390x (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-0:6.0.6-2.module+el8.3.0+6843+b3b42fcc.src (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-0:6.0.6-2.module+el8.3.0+6843+b3b42fcc.x86_64 (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-devel-0:6.0.6-2.module+el8.3.0+6843+b3b42fcc.aarch64 (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-devel-0:6.0.6-2.module+el8.3.0+6843+b3b42fcc.ppc64le (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-devel-0:6.0.6-2.module+el8.3.0+6843+b3b42fcc.s390x (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-devel-0:6.0.6-2.module+el8.3.0+6843+b3b42fcc.x86_64 (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-docs-0:6.0.6-2.module+el8.3.0+6843+b3b42fcc.aarch64 (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-docs-0:6.0.6-2.module+el8.3.0+6843+b3b42fcc.ppc64le (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-docs-0:6.0.6-2.module+el8.3.0+6843+b3b42fcc.s390x (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-docs-0:6.0.6-2.module+el8.3.0+6843+b3b42fcc.x86_64 (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-modules-0:0.15.0-5.module+el8.3.0+6843+b3b42fcc.aarch64 (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-modules-0:0.15.0-5.module+el8.3.0+6843+b3b42fcc.ppc64le (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-modules-0:0.15.0-5.module+el8.3.0+6843+b3b42fcc.s390x (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-modules-0:0.15.0-5.module+el8.3.0+6843+b3b42fcc.src (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-modules-0:0.15.0-5.module+el8.3.0+6843+b3b42fcc.x86_64 (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-modules-debuginfo-0:0.15.0-5.module+el8.3.0+6843+b3b42fcc.aarch64 (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-modules-debuginfo-0:0.15.0-5.module+el8.3.0+6843+b3b42fcc.ppc64le (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-modules-debuginfo-0:0.15.0-5.module+el8.3.0+6843+b3b42fcc.s390x (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-modules-debuginfo-0:0.15.0-5.module+el8.3.0+6843+b3b42fcc.x86_64 (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-modules-debugsource-0:0.15.0-5.module+el8.3.0+6843+b3b42fcc.aarch64 (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-modules-debugsource-0:0.15.0-5.module+el8.3.0+6843+b3b42fcc.ppc64le (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-modules-debugsource-0:0.15.0-5.module+el8.3.0+6843+b3b42fcc.s390x (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756
Fixedvarnish-modules-debugsource-0:0.15.0-5.module+el8.3.0+6843+b3b42fcc.x86_64 (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)redhat_csaf
For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
https://access.redhat.com/errata/RHSA-2020:4756

cvss

Technical severity, 0–10. One row per scoring source.

7.5

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–high · 3.1–7.5

v2.05mediumAV:N/AC:L/Au:N/C:P/I:N/A:Nprimary · NVD / NIST USexploitability 10 · impact 2.9

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:Nprimary · NVD / NIST USexploitability 3.9 · impact 3.6

v3.03.1lowCVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:Nsecondary · Red Hat Product Security US

v3.16.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-212USprimaryCWE-200US

affected products (41)

Products and version ranges known to be affected.

Amazon Linux 2all versionscert_bundDEcpe:/o:amazon:linux_2:-
Avaya Aura Experience Portalall versionscert_bundDEcpe:/a:avaya:aura_experience_portal:-
Debian Linuxall versionscert_bundDEcpe:/o:debian:debian_linux:-
NetApp ActiveIQ Unified Managerall versionscert_bundDEcpe:/a:netapp:active_iq_unified_manager:-::~~~vmware_vsphere~~
Open Source CentOSall versionscert_bundDEcpe:/o:centos:centos:-
Oracle Linuxall versionscert_bundDEcpe:/o:oracle:linux:-
Red Hat Enterprise Linux 8all versionscert_bundDEcpe:/o:redhat:enterprise_linux:8
SUSE Linuxall versionscert_bundDEcpe:/o:suse:suse_linux:-
Ubuntu Linuxall versionscert_bundDEcpe:/o:canonical:ubuntu_linux:-
n/a n/a≤ n/aenisa_euvdEU
opensuse backports sle= 15.0nvdUScpe:2.3:a:opensuse:backports_sle:*:*:*:*:*:*:*:*
opensuse leap= 15.1nvdUScpe:2.3:o:opensuse:leap:*:*:*:*:*:*:*:*
varnish-cache varnish cache6.1.0 → 6.2.2nvdUScpe:2.3:a:varnish-cache:varnish_cache:*:*:*:*:*:*:*:*
varnish-cache varnish cache6.3.0 → 6.3.1nvdUScpe:2.3:a:varnish-cache:varnish_cache:*:*:*:*:*:*:*:*
varnish-software varnish cache6.0.0 → 6.0.5nvdUScpe:2.3:a:varnish-software:varnish_cache:*:*:*:*:*:*:*:*
varnish-0:6.0.6-2.module+el8.3.0+6843+b3b42fcc.aarch64 (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)all versionsfixedredhat_csafUS
varnish-0:6.0.6-2.module+el8.3.0+6843+b3b42fcc.ppc64le (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)all versionsfixedredhat_csafUS
varnish-0:6.0.6-2.module+el8.3.0+6843+b3b42fcc.s390x (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)all versionsfixedredhat_csafUS
varnish-0:6.0.6-2.module+el8.3.0+6843+b3b42fcc.src (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)all versionsfixedredhat_csafUS
varnish-0:6.0.6-2.module+el8.3.0+6843+b3b42fcc.x86_64 (varnish:6) as a component of Red Hat Enterprise Linux AppStream (v. 8)all versionsfixedredhat_csafUS

showing 20 of 41

advisories (2)

Vendor and ecosystem advisories describing this.

RHSA-2020:4756Red Hat Security Advisory: varnish:6 security, bug fix, and enhancement update2020-11-04csaf · redhat_csafUS
An update for the varnish:6 module is now available for Red Hat Enterprise Linux 8. Red Hat Product Security has rated this update as having a security impact of Moderate. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.
WID-SEC-W-2022-0193Red Hat Enterprise Linux: Mehrere SchwachstellenDeutsch2020-11-03csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Red Hat Enterprise Linux ausnutzen, um die Verfügbarkeit, Integrität und Vertraulichkeit zu gefährden.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd cert_bund nvd redhat_csaf NVD CVE.org MITRE

published 2020-04-08modified 2026-06-17

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Related entries.

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Improper Removal of Sensitive Information Before Storage or Transfer in GitHub repository eventsource/eventsource prior to v2.0.2.
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+179 more

references (14)

External citations — patches, advisories, analysis.

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