Symfony: Ip Constraint public/private Modes Accept IPv4-Mapped and IPv4-Compatible IPv6 Addresses allowing SSRF Filter Bypass
Severity and exploitation
KEV coverage does not rule out exploitation.
Assessment vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:NAssessment vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:NSeverity
medium6.5CVSS measures technical severity, not the likelihood of an attack.
Known exploitation
Not listed in the checked CISA KEV catalog
Absence from CISA KEV does not rule out attacks.
Public exploit
Not established by this record
Missing evidence does not mean no public exploit exists.
Remediation
Fix status not established
No structured fix or guidance is available here. Check the latest publisher advisory.
What this means
The Symfony Validator component IpValidator incompletely classifies internal addresses in the filtered modes of the Ip constraint, so some internal addresses are accepted as public, which can lead to Server-Side Request Forgery (SSRF) in Symfony versions prior to 5.4.56, 6.x prior to 6.4.50, 7.x prior to 7.4.23, and 8.x prior to 8.1.11.
Source excerpt · CheckmarxAttack conditions
No attack-condition excerpt has been identified here. Review the full source description and references for authentication, network access, and configuration requirements.
Review supporting sources →Affected versions
Check the exact model, release, and any platform requirements against your installation.
sensiolabs · Checkmarx
symfony
4 ranges
sensiolabs · Checkmarx
symfony
Compare with this publisher’s ranges. This does not inspect your installation.
affected
0 → before 5.4.56
git versions
6.0.0 → before 6.4.50
git versions
7.0.0 → before 7.4.23
git versions
8.0.0 → before 8.1.11
git versions
Other versions: unaffected
What to do
Compare your installed product and version with the affected versions above. A matching product name alone does not confirm exposure.
No structured fix or remediation guidance is available here. Check the full source description and vendor’s latest advisory for a patch or workaround; do not assume another version is safe.
cve.new guidance unless attributed to a publisher. This page does not inspect your installation.
Public exploit evidence
No public exploit reference is identified in the imported evidence. This is not a claim that no exploit exists.
Original source description
Read the full publisher description
The Symfony Validator component IpValidator incompletely classifies internal addresses in the filtered modes of the Ip constraint, so some internal addresses are accepted as public, which can lead to Server-Side Request Forgery (SSRF) in Symfony versions prior to 5.4.56, 6.x prior to 6.4.50, 7.x prior to 7.4.23, and 8.x prior to 8.1.11.
In these modes, IpValidator relies on the PHP flags FILTER_FLAG_NO_PRIV_RANGE and FILTER_FLAG_NO_RES_RANGE to classify addresses as public, private, or reserved. These flags do not cover shared address space (100.64.0.0/10) or IPv4-mapped, IPv4-compatible, and 6to4 IPv6 addresses, which can embed internal IPv4 addresses. A value such as ::ffff:127.0.0.1 can therefore pass validation even though it points to an internal host. Applications that rely on the Ip constraint to reject internal addresses, for example before making a server-side request to a user-supplied address, can be exposed to SSRF.
References
2 sourcesInside the record
Evidence available
Describes the evidence in this view, not whether the product is safe.
Original records
CVE-2026-123125View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.
cve.new JSON →Underlying weaknesses
The source’s classification of what caused the vulnerability.
Environment requirements
These conditions apply together as specified by the publisher. A matching product name alone does not establish exposure.
Checkmarx · platform conditions
Any condition may hold
Any condition may hold
Vulnerable product
cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*From (inclusive): 0
Before: 5.4.56
Vulnerable product
cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*From (inclusive): 6.0.0
Before: 6.4.50
Vulnerable product
cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*From (inclusive): 7.0.0
Before: 7.4.23
Vulnerable product
cpe:2.3:a:sensiolabs:symfony:*:*:*:*:*:*:*:*From (inclusive): 8.0.0
Before: 8.1.11
Applicability preview
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]Contributing organizations · 2
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