NGINX ngx_http_js_module vulnerability

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.

Scores

EPSS (exploitation in 30 days)

0.21% · top 89% of all CVEs (5 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.3.

Weakness

• CWE-436 Interpretation Conflict (opens in a new tab)All about CWE-436 and its CVEs

Affected products

• F5 · NGINX JavaScript

  • affected 0.7.10 – < 1.0.2

What to do

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.

References (1)

• https://my.f5.com/manage/s/article/K000162615 (opens in a new tab)vendor-advisory

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-101019](https://trackcve.app/badge/CVE-2026-101019.svg)](https://trackcve.app/cve/CVE-2026-101019)

Record last updated 15 Oct 2026, 16:43 UTC.