How severe is CVE-2016-2403?

CVE-2016-2403 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2016-2403 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-2016-2403?

CVE-2016-2403 primarily affects Sensiolabs Symfony. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2016-2403?

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

When was CVE-2016-2403 published?

CVE-2016-2403 was published on 2017-02-07 and last updated on 2026-06-17.

CVE-2016-2403

CVE-2016-2403 is a critical-severity vulnerability in Sensiolabs Symfony with a CVSS 3.x base score of 9.8. 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-287.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 3% (87th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Sensiolabs Symfony
Published: 2017-02-07
Last modified: 2026-06-17

Description

Symfony before 2.8.6 and 3.x before 3.0.6 allows remote attackers to bypass authentication by logging in with an empty password and valid username, which triggers an unauthenticated bind.

Frequently asked questions

What is CVE-2016-2403?: Symfony before 2.8.6 and 3.x before 3.0.6 allows remote attackers to bypass authentication by logging in with an empty password and valid username, which triggers an unauthenticated bind.
How severe is CVE-2016-2403?: CVE-2016-2403 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2016-2403 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-2016-2403?: CVE-2016-2403 primarily affects Sensiolabs Symfony. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2016-2403?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2016-2403 published?: CVE-2016-2403 was published on 2017-02-07 and last updated on 2026-06-17.

References

Affected products (12)

cpe:2.3:a:sensiolabs:symfony:2.8.0:*:*:*:*:*:*:*
cpe:2.3:a:sensiolabs:symfony:2.8.1:*:*:*:*:*:*:*
cpe:2.3:a:sensiolabs:symfony:2.8.2:*:*:*:*:*:*:*
cpe:2.3:a:sensiolabs:symfony:2.8.3:*:*:*:*:*:*:*
cpe:2.3:a:sensiolabs:symfony:2.8.4:*:*:*:*:*:*:*
cpe:2.3:a:sensiolabs:symfony:2.8.5:*:*:*:*:*:*:*
cpe:2.3:a:sensiolabs:symfony:3.0.0:*:*:*:*:*:*:*
cpe:2.3:a:sensiolabs:symfony:3.0.1:*:*:*:*:*:*:*
cpe:2.3:a:sensiolabs:symfony:3.0.2:*:*:*:*:*:*:*
cpe:2.3:a:sensiolabs:symfony:3.0.3:*:*:*:*:*:*:*
cpe:2.3:a:sensiolabs:symfony:3.0.4:*:*:*:*:*:*:*
cpe:2.3:a:sensiolabs:symfony:3.0.5:*:*:*:*:*:*:*

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