How severe is CVE-2018-19131?

CVE-2018-19131 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2018-19131 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (87th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-19131?

CVE-2018-19131 affects Squid-cache Squid. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-19131?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2018-19131 published?

CVE-2018-19131 was published on 2018-11-09 and last updated on 2026-06-17.

CVE-2018-19131

CVE-2018-19131 is a medium-severity vulnerability in Squid-cache Squid with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v2: 4.3
EPSS exploit prediction: 3% (87th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Squid-cache Squid
Published: 2018-11-09
Last modified: 2026-06-17

Description

Squid before 4.4 has XSS via a crafted X.509 certificate during HTTP(S) error page generation for certificate errors.

Frequently asked questions

What is CVE-2018-19131?: Squid before 4.4 has XSS via a crafted X.509 certificate during HTTP(S) error page generation for certificate errors.
How severe is CVE-2018-19131?: CVE-2018-19131 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2018-19131 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (87th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-19131?: CVE-2018-19131 affects Squid-cache Squid. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-19131?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2018-19131 published?: CVE-2018-19131 was published on 2018-11-09 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:squid-cache:squid:*:*:*:*:*:*:*:*

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Threat intelligence

Threat-intel indicators referencing this CVE:

200.89.159.59 (ipv4-addr)
192.3.127.40 (ipv4-addr)