CVE-2019-20637

HIGHEPSS 76th pctl

7.5

CVSS v3

Description

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.

CWE-212

How to fix

Remediation Available

varnishDebian

Fixed in:6.4.0-1CVE-2019-20637

libvarnishapi1Ubuntu

Fixed in:5.2.1-1ubuntu0.1USN-5474-1

libvarnishapi2Ubuntu

Fixed in:6.2.1-2ubuntu0.1USN-5474-1

Fixed in:6.6.1-1ubuntu0.2USN-5474-1

varnishUbuntu

Fixed in:5.2.1-1ubuntu0.1USN-5474-1

Fixed in:6.2.1-2ubuntu0.1USN-5474-1

Fixed in:6.6.1-1ubuntu0.2USN-5474-1

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityNone

AvailabilityNone

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

Exploit Intelligence

1.75%probability of exploitation in 30 days

76thpercentile

Elevated risk: more likely to be exploited than 76% of all known CVEs.

References

Vendor Advisory1

varnish-cache.org

Third-Party Advisory2

Related Vulnerabilities

Other CWE-212 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2020-1940	High	7.5	4.5%	-	-
CVE-2022-29900	Medium	6.5	3.8%	-	Fix
CVE-2002-0704	High	7.5	3.2%	-	-
CVE-2020-15094	High	8.0	3.0%	-	Fix
CVE-2022-23633	High	7.4	2.2%	-	Fix
CVE-2019-19362	Medium	6.5	2.1%	-	-

Common questions

How do I fix CVE-2019-20637?

Published advisories record a fix for 4 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2019-20637 being actively exploited?

Not that we know of. CVE-2019-20637 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 1.7% is the estimated probability that it will be exploited in the next 30 days. That is higher than 76% of all scored CVEs.

How severe is CVE-2019-20637?

CVE-2019-20637 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2019-20637 affect?

Published advisories record a fix for varnish (Debian), libvarnishapi1 (Ubuntu), libvarnishapi2 (Ubuntu), varnish (Ubuntu). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.