Is CVE-2019-18678 in the CISA KEV catalog?

No. CVE-2019-18678 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2019-18678?

CVE-2019-18678 has a CVSS v3 base score of 5.3 (MEDIUM).

What is the EPSS score for CVE-2019-18678?

CVE-2019-18678 has an EPSS score of 10.93% (95th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2019-18678?

Upgrade squid on debian 11 to 4.9-1 or later. Fixes are available for 2 affected products.

CVE & CISA-KEV Catalog

CVE-2019-18678

MEDIUMEPSS 95th pctl

5.3

CVSS v3

NVD

Description

An issue was discovered in Squid 3.x and 4.x through 4.8. It allows attackers to smuggle HTTP requests through frontend software to a Squid instance that splits the HTTP Request pipeline differently. The resulting Response messages corrupt caches (between a client and Squid) with attacker-controlled content at arbitrary URLs. Effects are isolated to software between the attacker client and Squid. There are no effects on Squid itself, nor on any upstream servers. The issue is related to a request header containing whitespace between a header name and a colon.

CWE-444

How to fix

Remediation Available

squidDebian

Fixed in:4.9-1CVE-2019-18678

squid3Ubuntu

Fixed in:3.5.12-1ubuntu7.9USN-4213-1

Fixed in:3.5.27-1ubuntu1.4USN-4213-1

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

ConfidentialityNone

IntegrityLow

AvailabilityNone

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

Exploit Intelligence

10.93%probability of exploitation in 30 days

95thpercentile

Very high risk: more likely to be exploited than 95% of all known CVEs.

References

Patch1

github.com

Third-Party Advisory4

Release Notes1

squid-cache.org

Other references5

Related Vulnerabilities

Other CWE-444 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2022-22536	Critical	10.0	98%	KEV	-
CVE-2025-61884	High	7.5	98%	KEV + Ransom	-
CVE-2020-9490	High	7.5	90%	-	Fix
CVE-2023-41265	Critical	9.6	85%	KEV + Ransom	-
CVE-2023-25690	Critical	9.8	84%	-	Fix
CVE-2022-32214	Medium	6.5	81%	-	Fix

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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.