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Fencer Vulns
high 8.1

CVE-2019-18887 json

Symfony Http-Kernel has non-constant time comparison in UriSigner

published 2019-11-21 6 y ago modified 2026-06-17 4 mo ago also GHSA-q8hg-pf8v-cxrv , EUVD-2022-1515

cvss
8.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.3%
EPSS 1.3% chance of exploitation in 30 days, percentile 71%
public exploits
0
none known

Summary

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.

Patch / fix

  • packagist symfony/http-kernel 2.8.52, 3.4.35, 4.2.12, 4.3.8
  • packagist symfony/symfony 2.8.52, 3.4.35, 4.2.12, 4.3.8
  • symfony Debian 14, Debian 13, Debian 12 4.3.8+dfsg-1

debian advisories DEBIAN-CVE-2019-18887

Exploit prediction

1.34% chance of exploitation in the next 30 days, higher than 71% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P
GitHub 3.1 8.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
packagist symfony/http-kernel
>=2.2.0, <2.8.52
>=3.0.0, <3.4.35
>=4.0.0, <4.2.12
>=4.3.0, <4.3.8
2.8.52
3.4.35
4.2.12
4.3.8
packagist symfony/symfony
>=2.2.0, <2.8.52
>=3.0.0, <3.4.35
>=4.0.0, <4.2.12
>=4.3.0, <4.3.8
2.8.52
3.4.35
4.2.12
4.3.8

Classification

Weakness

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.