saml2: Improper Restriction of XML External Entity Reference
CVE-2024-52806 is a high-severity improper restriction of XML external entity reference vulnerability in saml2 from Simplesamlphp, with a CVSS 3.1 base score of 8.3 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 4.6.14, 5.0.0-alpha.18 as the first without the flaw, so updating saml2 to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.43% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update saml2 to 4.6.14 or 5.0.0-alpha.18, whichever matches your release line, or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Simplesamlphp | saml2 | < 4.6.14; >= 5.0.0-alpha.1, < 5.0.0-alpha.18; before 4.6.14; 5.0.0-alpha.1 and earlier; before 5.0.0-alpha.18 | 4.6.14, 5.0.0-alpha.18 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- LowSome restricted data can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- LowPerformance or availability is reduced.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L. Scored by CNA (github.com).
Official description
SimpleSAMLphp SAML2 library is a PHP library for SAML2 related functionality. When loading an (untrusted) XML document, for example the SAMLResponse, it's possible to induce an XXE. This vulnerability is fixed in 4.6.14 and 5.0.0-alpha.18.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Restriction of XML External Entity Reference
The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.
How developers prevent this class of flaw
- Many XML parsers and validators can be configured to disable external entity expansion.
More Improper Restriction of XML External Entity Reference vulnerabilities (CWE-611)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other vulnerabilities in saml2
- 7.5 High severity
- 8.7 High severity
- 8.6 High severity
- 7.5 High severity
Recent Improper Restriction of XML External Entity Reference vulnerabilities
- 8.8 High severity
- 7.5 High severity
- 7.5 High severity
- 8.2 High severity
- 9.2 Critical severity
- 8.6 High severity
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