CVSS 4.0
6.3 mediumCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:NCVE-2026-123125
Medium (6.3). EPSS 0.2% estimated probability of exploitation activity in the next 30 days.
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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.
Severity
CVSS 3.1
6.5 mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N- EPSS
- 0.2% estimated probability of exploitation activity in the next 30 days; 11th percentile. Scored 2026-11-10. A forecast for this CVE across the internet, not for your own systems.
- CISA's assessment (SSVC)
- Exploitation: none · Automatable: yes · Technical impact: partial, assessed 2026-11-05. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
- OWASP Top 10
- A01:2025 Broken Access Control
- Published
- Modified
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
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Explain CVE-2026-123125 for an engineer deciding whether to act. Use https://cve.bz/api/public/cves/CVE-2026-123125?via=ask-ai-copy and https://cve.bz/cve/CVE-2026-123125?via=ask-ai-copy as the source of truth: what is affected and which versions fix it, whether it is in CISA KEV, public exploits, and its EPSS (an internet-wide 30-day estimate of exploitation activity, not a forecast for my systems). If they give no fixed versions, use the CVE record https://cveawg.mitre.org/api/cve/CVE-2026-123125 or the vendor advisory, not third-party mirrors. Tell me how to check whether I am affected and how to verify a fix. Cite the sources and say where they are uncertain.Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this CVE's id and public links.
Linux distributions
| Distribution | Release | Package | Fixed in | Advisory |
|---|---|---|---|---|
| Debian | 12 | symfony | no fix listed | DEBIAN-CVE-2026-123125 |
| Debian | 13 | symfony | 6.4.50+dfsg-0+deb13u1 | DEBIAN-CVE-2026-123125 |
| Debian | 14 | symfony | 7.4.23+dfsg-1 | DEBIAN-CVE-2026-123125 |
| Ubuntu | 16.04:LTS, 26.04:LTS, 26.10 and 4 more | symfony | no fix listed | UBUNTU-CVE-2026-123125 |
From the distributions' data via OSV.dev: the Debian Security Tracker; Ubuntu Security Notices © Canonical Ltd., CC BY-SA 4.0. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Debian · Ubuntu.
Attack patterns (CAPEC)
- CAPEC-664 Server Side Request Forgery Likelihood: High · Severity: High
- CAPEC-3 Using Leading 'Ghost' Character Sequences to Bypass Input Filters Likelihood: Medium · Severity: Medium
- CAPEC-6 Argument Injection Likelihood: High · Severity: High
- CAPEC-15 Command Delimiters Likelihood: High · Severity: High
- CAPEC-43 Exploiting Multiple Input Interpretation Layers Likelihood: Medium · Severity: High
- CAPEC-71 Using Unicode Encoding to Bypass Validation Logic Likelihood: Medium · Severity: High
- CAPEC-73 User-Controlled Filename Likelihood: High · Severity: High
- CAPEC-85 AJAX Footprinting Likelihood: High · Severity: Low
- CAPEC-120 Double Encoding Likelihood: Low · Severity: Medium
- CAPEC-182 Flash Injection Likelihood: High · Severity: Medium
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.