An issue was discovered in Symfony 4.2.0 to 4.2.11 and 4.3.0 to 4.3.7.
An issue was discovered in Symfony 4.2.0 to 4.2.11 and 4.3.0 to 4.3.7. The ability to enumerate users was possible due to different handling depending on whether the user existed when making unauthorized attempts to use the switch users functionality. This is related to symfony/security.
- Published
- Nov 21, 2019
- Updated
- Jun 16, 2026
- EPSS
- 1.6% · 74th percentile
- CWE
- CWE-203
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Report tools
Action score
21
Monitor
Low priority for now.
- CVSS
- 21 / 40 · 5.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 1.6%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| sensiolabs | symfony | cpe:2.3:a:sensiolabs:symfony |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- sensiolabs symfony4.2.0 and later · up to 4.2.11 inclusive
- sensiolabs symfony4.3.0 and later · up to 4.3.7 inclusive
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | symfony | before 4.3.8+dfsg-1 | 4.3.8+dfsg-1 |
| Debian:8 | symfony | before 2.3.21+dfsg-4+deb8u6 | 2.3.21+dfsg-4+deb8u6 |
| Packagist | symfony/security-http | from 4.1.0 · before 4.2.12 | 4.2.12 |
| Packagist | symfony/security-http | from 4.3.0 · before 4.3.8 | 4.3.8 |
| Packagist | symfony/symfony | from 4.1.0 · before 4.2.12 | 4.2.12 |
| Packagist | symfony/symfony | from 4.3.0 · before 4.3.8 | 4.3.8 |
Same product
sensiolabs: all recordsOther highest-scoring records for the same primary product.
- CVE-2019-18889An issue was discovered in Symfony 3.4.0 through 3.4.34, 4.2.0 through 4.2.11, and 4.3.0 through 4.3.7.49Plan
- CVE-2018-14773An issue was discovered in Http Foundation in Symfony 2.7.0 through 2.7.48, 2.8.0 through 2.8.43, 3.3.0 through 3.3.17, 3.4.0 through 3.4.1343Plan
- CVE-2019-10910In Symfony before 2.7.51, 2.8.x before 2.8.50, 3.x before 3.4.26, 4.x before 4.1.12, and 4.2.x before 4.2.7, when service ids allow user inp41Plan
- CVE-2019-11325An issue was discovered in Symfony before 4.2.12 and 4.3.x before 4.3.8.40Plan
- CVE-2017-11365Certain Symfony products are affected by: Incorrect Access Control.40Plan
- CVE-2019-10913In Symfony before 2.7.51, 2.8.x before 2.8.50, 3.x before 3.4.26, 4.x before 4.1.12, and 4.2.x before 4.2.7, HTTP Methods provided as verbs 40Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:symfony | 4.3.8+dfsg-1 · Debian:12 | Package registry (OSV) |
| Packagist:symfony/security-http | 4.2.12 | Package registry (OSV) |
| Packagist:symfony/security-http | 4.3.8 | Package registry (OSV) |
| Packagist:symfony/symfony | 4.2.12 | Package registry (OSV) |
| Packagist:symfony/symfony | 4.3.8 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- low · data can be read
- Integrity
- none
- Availability
- none
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- Low
- Integrity impact
- None
- Availability impact
- None
Weakness class (CWE)
CWE-203 · Observable DiscrepancyCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
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References
- github.com/symfony/symfony/releases/tag/v4.3.8
- symfony.com/blog/cve-2019-18886-prevent-user-enumeration-using-switch-user-functionality
- symfony.com/blog/symfony-4-3-8-released
Vendor advisories and official records. Exploit/PoC links are deliberately left out.