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Fencer Vulns
medium 5.3

CVE-2019-18886 json

User enumeration leak using switch user functionality in Symfony

published 2019-11-21 6 y ago modified 2026-06-17 4 mo ago also GHSA-4vpc-5jx4-cfqg , EUVD-2019-0777

cvss
5.3
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.6%
EPSS 1.6% chance of exploitation in 30 days, percentile 75%
public exploits
0
none known

Summary

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.

Patch / fix

  • packagist symfony/security-http 4.2.12, 4.3.8
  • packagist symfony/symfony 4.2.12, 4.3.8
  • symfony Debian 14, Debian 13, Debian 12 4.3.8+dfsg-1

debian advisories DEBIAN-CVE-2019-18886

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2019-18886 updated cvss 5.3

php-symfony: User enumeration issue in symfony/security

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.55% chance of exploitation in the next 30 days, higher than 75% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N
GitHub 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected packages

ecosystem package affected fixed in
packagist symfony/security-http
>=4.1.0, <4.2.12
>=4.3.0, <4.3.8
4.2.12
4.3.8
packagist symfony/symfony
>=4.1.0, <4.2.12
>=4.3.0, <4.3.8
4.2.12
4.3.8

Classification

Weakness
  • CWE-203 Observable Discrepancy
  • CWE-200 Exposure of Sensitive Information to an Unauthorized Actor

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.