vulnerability / NVI-00018471 / Revision 1
samlify: XML Injection in AttributeValue Allows Privilege Escalation in Signed SAML Assertions
GitHub lists this reviewed advisory for samlify. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
samlify
source listed< 2.13.0
## Summary samlify’s template substitution only escapes attribute contexts. Values inserted into element text (e.g., ``) are not escaped. A normal user can inject XML markup into an attribute value (e.g., email, name) and add new `` elements inside the signed assertion. The IdP then signs the tampered assertion and the SP accepts the injected attributes as trusted. This allows privilege escalation when attributes are used for authorization (roles/groups). ## Root Cause `src/libsaml.ts` → `replaceTagsByValue()` only escapes placeholders when preceded by a quote (attribute context). Element text is inserted raw. The attribute builder inserts placeholders into element text: ``` {attrUserX} ``` Therefore, `…` is accepted and signed. ## Proof-of-concept - poc/attribute_injection.ts ```TS import { readFileSync } from 'fs'; import * as samlify from '../index'; import * as validator from '@authenio/samlify-xsd-schema-validator'; samlify.setSchemaValidator(validator); const { IdentityProvider, ServiceProvider, SamlLib: libsaml, Utility: util } = samlify as an
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database
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Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-34r5-q4jw-r36m ↗
GitHub Advisory Database · vendor advisory
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Public revision history
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- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.