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CVE-2019-20637

25
FAUCET Score

CVE-2019-20637 is a vulnerability in Varnish Cache versions prior to 6.0.5 LTS, 6.2.2, and 6.3.1, affecting various openSUSE and Varnish Cache products. The flaw involves a pointer not being cleared between client requests within the same connection, leading to information disclosure from the connection workspace, including data from previous requests or VCL-related temporary headers. Rated with a CVSS score of 7.5 (HIGH), this vulnerability is network-exploitable with low attack complexity, potentially exposing sensitive information without requiring user interaction. Currently, there is no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
>= 6.1.0, < 6.2.2CPE matchmatch criteria
cpe:2.3:a:varnish-cache:varnish_cache:*:*:*:*:-:*:*:*
>= 6.3.0, < 6.3.1CPE matchmatch criteria
cpe:2.3:a:varnish-cache:varnish_cache:*:*:*:*:-:*:*:*
>= 6.0.0, < 6.0.5CPE matchmatch criteria
cpe:2.3:a:varnish-software:varnish_cache:*:*:*:*:lts:*:*:*
15.0CPE matchmatch criteria
cpe:2.3:a:opensuse:backports_sle:15.0:sp1:*:*:*:*:*:*
15.1CPE matchmatch criteria
cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*

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:H/I:N/A:N

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

Exploit Intelligence

EPSS Score
1.75%
Probability of exploitation in next 30 days
EPSS Percentile
75.5%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.0175 is in the 58th percentile among its peer group of 51,485 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 (3)

redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: varnish:6-8030020200530080205.30b713e6
View patch
redhatvendor investigatingvia redhat_api
Product: Red Hat Software CollectionsFixed in: rh-varnish5-varnish
redhatno patchvia redhat_api
Product: Red Hat Software CollectionsFixed in: rh-varnish6-varnish

Vendor Advisories (1)

redhatCVE-2019-20637Low

varnish: not clearing pointer between two client requests leads to information disclosure

Oct 21, 2019

References

lists.opensuse.org / opensuse-security-announce/2020-06/msg00026.html
Mailing ListThird Party Advisory
lists.opensuse.org / opensuse-security-announce/2020-06/msg00031.html
Mailing ListThird Party Advisory
varnish-cache.org / security/VSV00004.html
Vendor Advisory