samlify: XML Injection in AttributeValue Allows Privilege Escalation in Signed SAML Assertions

published 2026-05-21 5 mo ago modified 2026-07-23 3 mo ago also GHSA-34r5-q4jw-r36m , EUVD-2026-35188

cvss: 8.8; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits: 0; none known

samlify is a Node.js library for SAML single sign-on. Prior to version 2.13.0, samlify’s template substitution only escapes attribute contexts. Values inserted into element text (e.g., <saml:AttributeValue>) are not escaped. A normal user can inject XML markup into an attribute value (e.g., email, name) and add new <saml:Attribute> 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). This issue has been patched in version 2.13.0.

Patch / fix

fixed in 2

npm samlify 2.13.0
samlify_project samlify 2.13.0

CISA SSVC

Exploitation: Proof of concept is public
Automatable: yes
Technical impact: partial
Assessed: 5 mo ago (2026-06-09)

Exploit prediction

0.47% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/tngan/samlify/security/advisories/GHSA-34r5-q4jw-r36m referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	4.0	8.7	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
CNA	4.0	8.7	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD	3.1	8.8	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem	package	affected	fixed in
npm	samlify	<2.13.0	2.13.0

Affected products

tngan samlify

Classification

Weakness

CWE-91 XML Injection

References

github.com /tngan/samlify/security/advisories/GHSA-34r5-q4jw-r36m
exploit, web, vendor-advisory
nvd.nist.gov /vuln/detail/CVE-2026-46490
advisory
github.com /tngan/samlify
package

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary