NGINX JavaScript (njs) has a vulnerability where the njs XML module exposes entity-backed XML attributes inconsistently with libxml2 canonicalization. In both the built-in njs and QuickJS backends during the canonicalization process, the $attr$Name getter may return undefined for an explicitly present attribute containing an internal entity reference. The $attrs getter may return a value derived only from the first attribute child. This may allow an unauthenticated attacker that invests significant effort in obtaining a genuinely signed document to skip validation while signature verification succeeds. An nginx-saml deployment is a confirmed affected consumer when run with the built-in njs backend.
Impact
In affected signed-XML consumers, an unauthenticated attacker can cause security-relevant attributes to appear absent or truncated while signature verification succeeds. In nginx-saml, this can bypass expiry, Destination, and request-correlation checks, enabling replay or acceptance of a response outside its intended context. It does not permit signature or identity forgery, or a direct availability impact. There is no control plane exposure; this is a data plane issue only.
Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
Analysis
No analysis available yet.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| F5 | NGINX JavaScript | unknown |
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Vendor Workaround
Applications processing signed XML should reject DTD-bearing input before calling xml.parse(). The check must cover the complete document after decoding its accepted input encoding; a parser-level DTD prohibition is preferable to a raw byte search for "<!DOCTYPE". Applications should also treat absent security-relevant attributes as validation failures rather than optional values. nginx-saml deployments should explicitly validate Destination, request correlation when unsolicited SSO is not intended, assertion validity, bearer SubjectConfirmation, Recipient, and SubjectConfirmationData InResponseTo.
Tracking
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No advisories yet.
| Link | Providers |
|---|---|
| https://my.f5.com/manage/s/article/K000162615 |
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Wed, 14 Oct 2026 15:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Description NGINX JavaScript (njs) has a vulnerability where the njs XML module exposes entity-backed XML attributes inconsistently with libxml2 canonicalization. In both the built-in njs and QuickJS backends during the canonicalization process, the $attr$Name getter may return undefined for an explicitly present attribute containing an internal entity reference. The $attrs getter may return a value derived only from the first attribute child. This may allow an unauthenticated attacker that invests significant effort in obtaining a genuinely signed document to skip validation while signature verification succeeds. An nginx-saml deployment is a confirmed affected consumer when run with the built-in njs backend. Impact In affected signed-XML consumers, an unauthenticated attacker can cause security-relevant attributes to appear absent or truncated while signature verification succeeds. In nginx-saml, this can bypass expiry, Destination, and request-correlation checks, enabling replay or acceptance of a response outside its intended context. It does not permit signature or identity forgery, or a direct availability impact. There is no control plane exposure; this is a data plane issue only. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated. | |
| Title | NGINX ngx_http_js_module vulnerability | |
| Weaknesses | CWE-436 | |
| References |
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| Metrics |
cvssV3_1
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Subscriptions
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MITRE
Status: PUBLISHED
Assigner: f5
Published:
Updated: 2026-10-14T14:40:29.685Z
Reserved: 2026-09-30T21:56:14.632Z
Link: CVE-2026-101019
Vulnrichment
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NVD
Status : Awaiting Analysis
Published: 2026-10-14T15:17:01.697
Modified: 2026-10-14T16:04:11.750
Link: CVE-2026-101019
Redhat
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OpenCVE Enrichment
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CWE-436
Interpretation Conflict