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Vulnerability details: VCID-zb85-shgd-9qcq
Vulnerability ID VCID-zb85-shgd-9qcq
Aliases CVE-2019-20637
Summary 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.
Status Published
Exploitability 0.5
Weighted Severity 6.8
Risk 3.4
Affected and Fixed Packages Package Details
Weaknesses (2)
CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
CWE-212 Improper Removal of Sensitive Information Before Storage or Transfer
System Score Found at
cvssv3 3.1 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2019-20637.json
epss 0.00478 https://api.first.org/data/v1/epss?cve=CVE-2019-20637
epss 0.00478 https://api.first.org/data/v1/epss?cve=CVE-2019-20637
epss 0.00478 https://api.first.org/data/v1/epss?cve=CVE-2019-20637
epss 0.00478 https://api.first.org/data/v1/epss?cve=CVE-2019-20637
epss 0.00478 https://api.first.org/data/v1/epss?cve=CVE-2019-20637
epss 0.00478 https://api.first.org/data/v1/epss?cve=CVE-2019-20637
epss 0.00478 https://api.first.org/data/v1/epss?cve=CVE-2019-20637
epss 0.00478 https://api.first.org/data/v1/epss?cve=CVE-2019-20637
epss 0.00478 https://api.first.org/data/v1/epss?cve=CVE-2019-20637
epss 0.00478 https://api.first.org/data/v1/epss?cve=CVE-2019-20637
epss 0.00478 https://api.first.org/data/v1/epss?cve=CVE-2019-20637
epss 0.00478 https://api.first.org/data/v1/epss?cve=CVE-2019-20637
epss 0.00478 https://api.first.org/data/v1/epss?cve=CVE-2019-20637
cvssv2 5.0 https://nvd.nist.gov/vuln/detail/CVE-2019-20637
cvssv3.1 7.5 https://nvd.nist.gov/vuln/detail/CVE-2019-20637
Reference id Reference type URL
http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00026.html
http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00031.html
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2019-20637.json
https://api.first.org/data/v1/epss?cve=CVE-2019-20637
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-20637
http://varnish-cache.org/security/VSV00004.html#vsv00004
1772362 https://bugzilla.redhat.com/show_bug.cgi?id=1772362
956305 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=956305
cpe:2.3:a:opensuse:backports_sle:15.0:sp1:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:opensuse:backports_sle:15.0:sp1:*:*:*:*:*:*
cpe:2.3:a:varnish-cache:varnish_cache:*:*:*:*:-:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:varnish-cache:varnish_cache:*:*:*:*:-:*:*:*
cpe:2.3:a:varnish-software:varnish_cache:*:*:*:*:lts:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:varnish-software:varnish_cache:*:*:*:*:lts:*:*:*
cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*
CVE-2019-20637 https://nvd.nist.gov/vuln/detail/CVE-2019-20637
RHSA-2020:4756 https://access.redhat.com/errata/RHSA-2020:4756
USN-5474-1 https://usn.ubuntu.com/5474-1/
No exploits are available.
Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2019-20637.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: AV:N/AC:L/Au:N/C:P/I:N/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2019-20637
Exploitability (E) Access Vector (AV) Access Complexity (AC) Authentication (Au) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

high

functional

unproven

proof_of_concept

not_defined

local

adjacent_network

network

high

medium

low

multiple

single

none

none

partial

complete

none

partial

complete

none

partial

complete
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2019-20637
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.64008
EPSS Score 0.00478
Published At June 30, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2025-07-01T12:11:51.303075+00:00 Ubuntu USN Importer Import https://usn.ubuntu.com/5474-1/ 36.1.3