SensioLabs Symfony up to 5.4.55/6.4.49/7.4.22/8.1.10 Config XmlUtils::parse xml external entity reference

Summaryinfo

A vulnerability marked as critical has been reported in SensioLabs Symfony up to 5.4.55/6.4.49/7.4.22/8.1.10. This issue affects the function XmlUtils::parse of the component Config. Performing a manipulation results in xml external entity reference. This vulnerability is identified as CVE-2026-123824. The attack can be initiated remotely. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in SensioLabs Symfony up to 5.4.55/6.4.49/7.4.22/8.1.10. It has been classified as critical. This affects the function XmlUtils::parse of the component Config. The manipulation with an unknown input leads to a xml external entity reference vulnerability. CWE is classifying the issue as CWE-611. The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-123824 since 11/06/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 5.4.56, 6.4.50, 7.4.23 or 8.1.11 eliminates this vulnerability.

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• Programming Tool Software

Vendor

• SensioLabs

Name

• Symfony

Version

• 5.4.0
• 5.4.1
• 5.4.2
• 5.4.3
• 5.4.4
• 5.4.5
• 5.4.6
• 5.4.7
• 5.4.8
• 5.4.9
• 5.4.10
• 5.4.11
• 5.4.12
• 5.4.13
• 5.4.14
• 5.4.15
• 5.4.16
• 5.4.17
• 5.4.18
• 5.4.19
• 5.4.20
• 5.4.21
• 5.4.22
• 5.4.23
• 5.4.24
• 5.4.25
• 5.4.26
• 5.4.27
• 5.4.28
• 5.4.29
• 5.4.30
• 5.4.31
• 5.4.32
• 5.4.33
• 5.4.34
• 5.4.35
• 5.4.36
• 5.4.37
• 5.4.38
• 5.4.39
• 5.4.40
• 5.4.41
• 5.4.42
• 5.4.43
• 5.4.44
• 5.4.45
• 5.4.46
• 5.4.47
• 5.4.48
• 5.4.49
• 5.4.50
• 5.4.51
• 5.4.52
• 5.4.53
• 5.4.54
• 5.4.55
• 6.4.0
• 6.4.1
• 6.4.2
• 6.4.3
• 6.4.4
• 6.4.5
• 6.4.6
• 6.4.7
• 6.4.8
• 6.4.9
• 6.4.10
• 6.4.11
• 6.4.12
• 6.4.13
• 6.4.14
• 6.4.15
• 6.4.16
• 6.4.17
• 6.4.18
• 6.4.19
• 6.4.20
• 6.4.21
• 6.4.22
• 6.4.23
• 6.4.24
• 6.4.25
• 6.4.26
• 6.4.27
• 6.4.28
• 6.4.29
• 6.4.30
• 6.4.31
• 6.4.32
• 6.4.33
• 6.4.34
• 6.4.35
• 6.4.36
• 6.4.37
• 6.4.38
• 6.4.39
• 6.4.40
• 6.4.41
• 6.4.42
• 6.4.43
• 6.4.44
• 6.4.45
• 6.4.46
• 6.4.47
• 6.4.48
• 6.4.49
• 7.4.0
• 7.4.1
• 7.4.2
• 7.4.3
• 7.4.4
• 7.4.5
• 7.4.6
• 7.4.7
• 7.4.8
• 7.4.9
• 7.4.10
• 7.4.11
• 7.4.12
• 7.4.13
• 7.4.14
• 7.4.15
• 7.4.16
• 7.4.17
• 7.4.18
• 7.4.19
• 7.4.20
• 7.4.21
• 7.4.22
• 8.1.0
• 8.1.1
• 8.1.2
• 8.1.3
• 8.1.4
• 8.1.5
• 8.1.6
• 8.1.7
• 8.1.8
• 8.1.9
• 8.1.10

License

• open-source

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Entryinfo

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