CVE-2026-101019

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of data exposure.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

1. 2026-09-30 21:56 UTC ReservedThe CVE id was reserved by its CNA
2. 2026-10-14 15:17 UTC PublishedDisclosed publicly on CVE.org and NVD
3. 2026-10-15 17:17 UTC Last updatedMost recent change to the record

Details

Published

2026-10-14 15:17 UTC

Last modified

2026-10-15 17:17 UTC

Exploit probability

0.2% · EPSS, next 30 days

Weakness

CWE-436

Record status

Awaiting Analysis

Attack profile CVSS 4.0 · 8.3

Attack vector

Network

Complexity

Low

Attack requirements

Present

Privileges needed

None

User interaction

None

Confidentiality

High

Integrity

Low

Availability

None