CVE-2026-123125
Symfony: Ip Constraint public/private Modes Accept IPv4-Mapped and IPv4-Compatible IPv6 Addresses allowing SSRF Filter Bypass
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
6.3
Symfony: Ip Constraint public/private Modes Accept IPv4-Mapped and IPv4-Compatible IPv6 Addresses allowing SSRF Filter Bypass
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.
- Record
CVE-2026-123125- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N - CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-184, CWE-918
- Updated
- 2026-11-05
EUVDEUVD-2026-117557
6.3
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.
- Record
EUVD-2026-117557- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N - Updated
- 2026-11-05
NVD
6.3
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.
- Record
CVE-2026-123125- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-184, CWE-918
- Updated
- 2026-11-07
OSV
6.3
Symfony: Ip Constraint public/private Modes Accept IPv4-Mapped and IPv4-Compatible IPv6 Addresses allowing SSRF Filter Bypass
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.
- Record
CVE-2026-123125- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N - Weakness
- CWE-184, CWE-918
- Updated
- 2026-11-07
OSVDEBIAN-CVE-2026-123125
6.3
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.
- Record
DEBIAN-CVE-2026-123125- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Updated
- 2026-11-07
OSVUBUNTU-CVE-2026-123125
6.3
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.
- Record
UBUNTU-CVE-2026-123125- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N - CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N - Updated
- 2026-11-07
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
symfonyDebian:12 |
All versions, plus listed versions 5.4.23+dfsg-15.4.23+dfsg-1+deb12u15.4.23+dfsg-1+deb12u25.4.23+dfsg-1+deb12u35.4.23+dfsg-1+deb12u4 Show 45 moreShow less5.4.23+dfsg-1+deb12u55.4.24+dfsg-15.4.25+dfsg-15.4.27+dfsg-15.4.28+dfsg-15.4.29+dfsg-15.4.30+dfsg-15.4.31+dfsg-15.4.31+dfsg-25.4.32+dfsg-15.4.33+dfsg-15.4.34+dfsg-15.4.34+dfsg-25.4.35+dfsg-15.4.35+dfsg-25.4.35+dfsg-35.4.52+dfsg-0+deb12u15.4.53+dfsg-0+deb12u16.3.0+dfsg-16.3.0~rc1+dfsg-16.3.0~rc2+dfsg-16.3.1+dfsg-16.3.3+dfsg-16.3.4+dfsg-16.3.5+dfsg-16.3.6+dfsg-16.3.7+dfsg-16.4.0+dfsg-16.4.0~beta2+dfsg-16.4.0~beta3+dfsg-16.4.0~rc1+dfsg-16.4.0~rc2+dfsg-16.4.1+dfsg-16.4.10+dfsg-16.4.11+dfsg-16.4.12+dfsg-16.4.13+dfsg-16.4.14+dfsg-16.4.15+dfsg-16.4.16+dfsg-16.4.16+dfsg-26.4.17+dfsg-16.4.17+dfsg-26.4.17+dfsg-36.4.17+dfsg-4 |
None known |
symfonyDebian:13 |
All versions, plus listed versions 6.4.21+dfsg-26.4.21+dfsg-2+deb13u16.4.24+dfsg-16.4.25+dfsg-16.4.40+dfsg-0+deb13u1 Show 45 moreShow less6.4.41+dfsg-0+deb13u16.4.49+dfsg-0+deb13u17.0.4+dfsg-17.0.5+dfsg-17.0.6+dfsg-17.0.7+dfsg-17.1.0~beta1+dfsg-17.1.0~rc1+dfsg-17.1.2+dfsg-17.1.3+dfsg-17.1.4+dfsg-17.1.5+dfsg-17.2.0~beta1+dfsg-17.2.0~beta2+dfsg-17.2.0~rc1+dfsg-17.2.1+dfsg-17.2.2+dfsg-17.2.3+dfsg-17.2.4+dfsg-17.2.5+dfsg-17.2.6-17.3.0+dfsg-17.3.0~beta1+dfsg-17.3.0~beta2+dfsg-17.3.0~rc1+dfsg-17.3.1+dfsg-17.3.2+dfsg-17.3.3+dfsg-17.3.4+dfsg-17.3.5-17.4.0+dfsg-17.4.0+dfsg-27.4.0~beta1-17.4.0~beta1-27.4.0~beta2+dfsg-17.4.0~beta2+dfsg-27.4.0~beta2+dfsg-37.4.0~rc1+dfsg-17.4.0~rc2+dfsg-17.4.0~rc3+dfsg-17.4.10+dfsg-17.4.12+dfsg-17.4.13+dfsg-17.4.13+dfsg-27.4.14+dfsg-1 |
None known |
symfonyDebian:14 |
before 7.4.23+dfsg-1, plus listed versions 6.4.21+dfsg-26.4.24+dfsg-16.4.25+dfsg-17.0.4+dfsg-17.0.5+dfsg-1 Show 45 moreShow less7.0.6+dfsg-17.0.7+dfsg-17.1.0~beta1+dfsg-17.1.0~rc1+dfsg-17.1.2+dfsg-17.1.3+dfsg-17.1.4+dfsg-17.1.5+dfsg-17.2.0~beta1+dfsg-17.2.0~beta2+dfsg-17.2.0~rc1+dfsg-17.2.1+dfsg-17.2.2+dfsg-17.2.3+dfsg-17.2.4+dfsg-17.2.5+dfsg-17.2.6-17.3.0+dfsg-17.3.0~beta1+dfsg-17.3.0~beta2+dfsg-17.3.0~rc1+dfsg-17.3.1+dfsg-17.3.2+dfsg-17.3.3+dfsg-17.3.4+dfsg-17.3.5-17.4.0+dfsg-17.4.0+dfsg-27.4.0~beta1-17.4.0~beta1-27.4.0~beta2+dfsg-17.4.0~beta2+dfsg-27.4.0~beta2+dfsg-37.4.0~rc1+dfsg-17.4.0~rc2+dfsg-17.4.0~rc3+dfsg-17.4.10+dfsg-17.4.12+dfsg-17.4.13+dfsg-17.4.13+dfsg-27.4.14+dfsg-17.4.15+dfsg-17.4.15+dfsg-27.4.16+dfsg-17.4.17+dfsg-1 |
7.4.23+dfsg-1 |
symfonyUbuntu:16.04:LTS |
All versions, plus listed versions 2.7.1+dfsg-12.7.5+dfsg-12.7.9+dfsg-12.7.9+dfsg-1ubuntu22.7.10-0ubuntu2 |
None known |
symfonyUbuntu:Pro:18.04:LTS |
All versions, plus listed versions 2.8.7+dfsg-1.3ubuntu13.4.3+dfsg-1ubuntu43.4.6+dfsg-13.4.6+dfsg-1ubuntu0.13.4.6+dfsg-1ubuntu0.1+esm13.4.6+dfsg-1ubuntu0.1+esm2 |
None known |
symfonyUbuntu:Pro:20.04:LTS |
All versions, plus listed versions 4.3.4+dfsg-1ubuntu14.3.8+dfsg-1ubuntu14.3.8+dfsg-1ubuntu1+esm14.3.8+dfsg-1ubuntu1+esm2 |
None known |
symfonyUbuntu:Pro:22.04:LTS |
All versions, plus listed versions 5.2.6+dfsg-1ubuntu75.4.4+dfsg-1ubuntu85.4.4+dfsg-1ubuntu8+esm1 |
None known |
symfonyUbuntu:Pro:24.04:LTS |
All versions, plus listed versions 5.4.23+dfsg-1ubuntu15.4.35+dfsg-3ubuntu16.4.5+dfsg-3ubuntu26.4.5+dfsg-3ubuntu36.4.5+dfsg-3ubuntu3+esm1 |
None known |
symfonyUbuntu:26.10 |
All versions, plus listed versions 7.4.7+dfsg-1ubuntu17.4.9+dfsg-1ubuntu17.4.13+dfsg-2ubuntu17.4.14+dfsg-1ubuntu27.4.15+dfsg-2ubuntu27.4.16+dfsg-1ubuntu2 |
None known |
symfonyUbuntu:26.04:LTS |
All versions, plus listed versions 6.4.24+dfsg-17.4.5+dfsg-1ubuntu17.4.6+dfsg-2ubuntu17.4.7+dfsg-1ubuntu1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | OSV | |
| references | OSV | |
| affected, aliases, references | NVD, OSV | |
| affected, aliases, references | OSV | |
| aliases, references | CVE List, NVD, OSV | |
| aliases, products, published | EUVD | |
| first indexed | CVE List |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-123125 is a medium vulnerability (CVSS 6.3) in Sensiolabs Symfony, published November 5, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.21%, the 10th percentile. Fixed in symfony 7.4.23+dfsg-1.
References
github.com/symfony/symfony/security/advisories/GHSA-4qpf-57w4-m3wc
github.com/symfony/symfony/commit/3bf8ea37fcb402c5ecc502a3f63012df85a7572e
packagist.org/packages/symfony/validator
github.com/CVEProject/cvelistV5/tree/main/cves/2026/123xxx/CVE-2026-123125.json
nvd.nist.gov/vuln/detail/CVE-2026-123125
github.com/symfony/validator
security-tracker.debian.org/tracker/CVE-2026-123125
ubuntu.com/security/CVE-2026-123125
cve.org/CVERecord?id=CVE-2026-123125
Left out here: 183 versions. The JSON record has them.