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Fencer Vulns
medium 6.5

CVE-2023-46733 json

Symfony possible session fixation vulnerability

published 2023-11-10 2 y ago modified 2026-09-10 1 mo ago also BIT-symfony-2023-46733 , EUVD-2023-2996 , GHSA-m2wj-r6g3-fxfx

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 53%
public exploits
0
none known

Summary

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Starting in versions 5.4.21 and 6.2.7 and prior to versions 5.4.31 and 6.3.8, `SessionStrategyListener` does not migrate the session after every successful login. It does so only in case the logged in user changes by means of checking the user identifier. In some use cases, the user identifier doesn't change between the verification phase and the successful login, while the token itself changes from one type (partially-authenticated) to another (fully-authenticated). When this happens, the session id should be regenerated to prevent possible session fixations, which is not the case at the moment. As of versions 5.4.31 and 6.3.8, Symfony now checks the type of the token in addition to the user identifier before deciding whether the session id should be regenerated.

Patch / fix

  • packagist symfony/security-http 5.4.31, 6.3.8
  • packagist symfony/symfony 5.4.31, 6.3.8
  • bitnami symfony 5.4.31, 6.3.8
  • sensiolabs symfony 5.4.31, 6.3.8
  • symfony Debian 12 5.4.23+dfsg-1+deb12u1
  • symfony Debian 14, Debian 13 5.4.31+dfsg-1

debian advisories DEBIAN-CVE-2023-46733

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-2023-46733 updated cvss 5.4

php-symfony: possible session fixation

  • 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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.69% chance of exploitation in the next 30 days, higher than 53% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
GitHub 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
OSV 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Affected packages

ecosystem package affected fixed in
packagist symfony/security-http
>=5.4.21, <5.4.31
>=6.2.7, <6.3.8
5.4.31
6.3.8
packagist symfony/symfony
>=5.4.21, <5.4.31
>=6.2.7, <6.3.8
5.4.31
6.3.8
bitnami symfony
>=5.4.21, <5.4.31
>=6.2.7, <6.3.8
5.4.31
6.3.8

Affected products

  • symfony symfony

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.