CVE-2026-123824

Symfony: XXE (Local File Read) in Config XmlUtils::parse() via validateOnParse = true

Published Nov 6, 2026 CVSS 4.0 · 2.3 Low EPSS < 1% KEV · Not listed

Description

The Symfony Config component XmlUtils::parse() enables DTD validation before rejecting documents that carry a doctype, allowing XML external entity (XXE) injection 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. A remote attacker who can supply XML to this method can determine whether local files exist, cause a denial of service, and, in some configurations, exfiltrate local file content via a crafted XML document whose doctype declares an external file:// entity.
XmlUtils::parse() sets $dom->validateOnParse = true before calling loadXML() and only rejects documents carrying a doctype afterwards. Enabling DTD validation makes libxml resolve external entities during loadXML(), and LIBXML_NONET blocks http:// but not file://, so a file:// entity is read from disk before the doctype rejection runs. The content of the file is not returned to the caller, but the distinct libxml error for a missing path reveals whether a file exists, and an entity pointing at a large or slow file causes a denial of service. If the application registers a network-capable stream wrapper such as s3://, a parameter entity can also send the content of a local file to an external server. This is the same issue as CVE-2026-45071, which was fixed in the DomCrawler component but not in Config.

Applications are affected if they pass untrusted XML to XmlUtils::parse() directly. The Symfony components that call it process developer-provided or operator-configured sources, such as configuration files and the XLIFF documents fetched by the translation providers.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

sensiolabs

symfony

unaffected

Version	Status	Constraints
`0`	affected	< 5.4.56
`6.0.0`	affected	< 6.4.50
`7.0.0`	affected	< 7.4.23
`8.0.0`	affected	< 8.1.11

No data.

Vendor Product Versions

Sensiolabs

Symfony

Version	Status	Scheme	Platform
`[0,5.4.56)`	affected	generic	—
`[6.0.0,6.4.50)`	affected	semver	—
`[7.0.0,7.4.23)`	affected	semver	—
`[8.0.0,8.1.11)`	affected	semver	—

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

No advisories available

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact Low

Vulnerable System Availability Impact Low

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact Low

Integrity Impact Low

Availability Impact Low

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.272% probability within 30 days)

Exploitation none

Automatable no

Technical Impact partial

References

Link	Providers
https://github.com/symfony/symfony/commit/334ef21a6039355c05b123e7df60699be0e28da3
https://github.com/symfony/symfony/security/advisories/GHSA-5jff-8h8q-r5qx

History

Nov 7, 2026 7:30 AM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Nov 6, 2026 9:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		cvssV3_1 `{'score': 6.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L'}`

Nov 6, 2026 5:30 PM Description updated. Title updated. First appearance in the feed. Weaknesses updated. Affected versions updated. Affected vendors updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		The Symfony Config component XmlUtils::parse() enables DTD validation before rejecting documents that carry a doctype, allowing XML external entity (XXE) injection 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. A remote attacker who can supply XML to this method can determine whether local files exist, cause a denial of service, and, in some configurations, exfiltrate local file content via a crafted XML document whose doctype declares an external file:// entity. XmlUtils::parse() sets $dom->validateOnParse = true before calling loadXML() and only rejects documents carrying a doctype afterwards. Enabling DTD validation makes libxml resolve external entities during loadXML(), and LIBXML_NONET blocks http:// but not file://, so a file:// entity is read from disk before the doctype rejection runs. The content of the file is not returned to the caller, but the distinct libxml error for a missing path reveals whether a file exists, and an entity pointing at a large or slow file causes a denial of service. If the application registers a network-capable stream wrapper such as s3://, a parameter entity can also send the content of a local file to an external server. This is the same issue as CVE-2026-45071, which was fixed in the DomCrawler component but not in Config. Applications are affected if they pass untrusted XML to XmlUtils::parse() directly. The Symfony components that call it process developer-provided or operator-configured sources, such as configuration files and the XLIFF documents fetched by the translation providers.
Title		Symfony: XXE (Local File Read) in Config XmlUtils::parse() via validateOnParse = true
First Time appeared		Sensiolabs Sensiolabs symfony
Weaknesses		CWE-611
CPEs		cpe:2.3:a:sensiolabs:symfony::::::::
Vendors & Products		Sensiolabs Sensiolabs symfony
References		https://github.com/symfony/symfony/commit/334ef21a6039355c05b123e7df60699be0e28da3 https://github.com/symfony/symfony/security/advisories/GHSA-5jff-8h8q-r5qx
Metrics		cvssV4_0 `{'score': 2.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N'}`