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TI-2026-85494 Aliases CVE-2026-123125

Symfony Ip constraint accepts internal addresses as public

Priority LOW 33CWE-184Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
Present
Impact type
—
Confidentiality · integrity · availability
None · None · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

Symfony versions before 5.4.56, from 6.0.0 before 6.4.50, from 7.0.0 before 7.4.23, and from 8.0.0 before 8.1.11 are affected in the public and private modes of the Ip constraint in the Validator component. IpValidator relies on PHP filter flags that miss shared address space (100.64.0.0/10) and IPv4-mapped, IPv4-compatible and 6to4 IPv6 addresses, so internal addresses such as ::ffff:127.0.0.1 can pass as public (CWE-184). An unauthenticated remote attacker can submit such an address to an application that uses the constraint to block internal targets, which can lead to server-side request forgery.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00207 10th percentileScored 2026-11-07
Fix Fixed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

No affected products listed by the sources yet.

Remediation

Upgrade Symfony to 5.4.56, 6.4.50, 7.4.23 or 8.1.11, matching the release branch in use.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    sensiolabs symfony 5.4.56, 6.4.50 and 2 more versions

    2 records Highest priority Priority LOW 2 LOW

    Other records, highest priority first

    • TI-2026-85405 DNS rebinding in Symfony HttpClient exposes internal hosts and portsPriority LOW 11
    Show all 2 records →

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-11-05 Threatist record created from CVE-2026-123125
  2. 2026-11-05 CVSS score added · CISA ADP
  3. 2026-11-05 CISA SSVC decision points changed
  4. 2026-11-05 Priority changed: MEDIUM → LOW
  5. 2026-11-06 Affected versions changed · Red Hat
  6. 2026-11-06 CVSS score added · Red Hat

References

Patch 1

Advisory 1

  • TI-2019-13616 An issue was discovered in Symfony 3.4.0 through 3.4.34, 4.2.0 through 4.2.11, and 4.3.0… CVSS 3.1CRITICAL 9.8
  • TI-2018-10604 An issue was discovered in Http Foundation in Symfony 2.7.0 through 2.7.48, 2.8.0 through… CVSS 3.1MEDIUM 6.5
  • TI-2019-08131 In 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… CVSS 3.1CRITICAL 9.8
  • TI-2016-02159 Symfony before 2.8.6 and 3.x before 3.0.6 allows remote attackers to bypass… CVSS 3.0CRITICAL 9.8
  • TI-2019-08459 An issue was discovered in Symfony before 4.2.12 and 4.3.x before 4.3.8. CVSS 3.1CRITICAL 9.8
  • TI-2018-08136 An issue was discovered in the Ldap component in Symfony 2.8.x before 2.8.37, 3.3.x… CVSS 3.0CRITICAL 9.8
See all 107 →

Sources

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