How severe is CVE-2019-18887?

CVE-2019-18887 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2019-18887 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-18887?

CVE-2019-18887 primarily affects Sensiolabs Symfony. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-18887?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2019-18887 published?

CVE-2019-18887 was published on 2019-11-21 and last updated on 2026-06-17.

CVE-2019-18887

CVE-2019-18887 is a high-severity vulnerability in Sensiolabs Symfony with a CVSS 3.x base score of 8.1. 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-203.

Key facts

Severity: High (CVSS 3.x base score 8.1)
CVSS v2: 6.8
EPSS exploit prediction: 1% (68th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-203
Affected product: Sensiolabs Symfony
Published: 2019-11-21
Last modified: 2026-06-17

Description

An issue was discovered in Symfony 2.8.0 through 2.8.50, 3.4.0 through 3.4.34, 4.2.0 through 4.2.11, and 4.3.0 through 4.3.7. The UriSigner was subject to timing attacks. This is related to symfony/http-kernel.

Frequently asked questions

What is CVE-2019-18887?: An issue was discovered in Symfony 2.8.0 through 2.8.50, 3.4.0 through 3.4.34, 4.2.0 through 4.2.11, and 4.3.0 through 4.3.7. The UriSigner was subject to timing attacks. This is related to symfony/http-kernel.
How severe is CVE-2019-18887?: CVE-2019-18887 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2019-18887 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (68th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-18887?: CVE-2019-18887 primarily affects Sensiolabs Symfony. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-18887?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2019-18887 published?: CVE-2019-18887 was published on 2019-11-21 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:30:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*

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