Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessLure authenticated operator to attacker page
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DeliveryBrowser sends forged cross-site request
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ExploitReferrerFilter accepts weak origin evidence
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ExecutionRequest processed as trusted
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ImpactLimited unauthorized state change
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A07:2025 - Authentication Failures
ASVS 5.0
V6 - Authentication Origin validation
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| Exploitation Conditions | Applies to Apache Sling Security Bundle before 1.3.2 where the ReferrerFilter is used as the cross-site request protection control. Exploitation targets the filter's origin-validation logic, which accepts evidence weaker than the true origin, allowing cross-site requests that should be blocked. Realistic exploitation is limited by requiring an authenticated victim's session/browser to issue the forged request (CSRF-style user interaction) and by the low per-request impact; instances not relying on ReferrerFilter for protection, or already on 1.3.2+, are not affected. |
| Impact | The vendor (Apache) rates this 7.3 with vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L, implying trivial unauthenticated network exploitation with low impact across all three dimensions. The multi-source signals argue against treating this as a top priority: EPSS is only 0.13% (3rd percentile), it is NOT on CISA KEV, and no public exploit code was identified. The 7.3 is driven almost entirely by PR:N/UI:N/AC:L rather than by impact, since C/I/A are all Low. There is also internal tension in the CVSS: the ReferrerFilter is a CSRF/cross-site protection control, and bypassing origin evidence realistically requires a victim's browser to issue the forged request, which points to UI:R rather than UI:N - verify with the vendor advisory. Net: this is a defense-control-weakening (origin validation, CWE-346) issue, real but low-severity, better characterized as a hardening regression than an actively-dangerous flaw. |
| Exploit ScenarioDerived | An attacker hosts a malicious page and lures an authenticated Sling/AEM operator to it; because the ReferrerFilter accepts weaker-than-origin evidence, a cross-site request that should be rejected is accepted, allowing a forged state-changing request against the Sling instance. No public exploit code was identified, and the low CVSS impact metrics (C:L/I:L/A:L) indicate limited per-request effect rather than full compromise. |
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Alert meAnalysisAIv2 – Sep 23, 2026
Origin-validation bypass in the Apache Sling Security Bundle before 1.3.2 allows a remote attacker to defeat the ReferrerFilter when that filter is relied upon as the cross-site request protection control, so cross-site requests that should have been blocked are accepted, yielding low-level confidentiality, integrity, and availability impact. Exploitation requires the victim to be lured into a crafted request carrying an authenticated session (CSRF-style user interaction), and only deployments that depend on ReferrerFilter for origin validation are exposed. Apache rates this 7.3 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L), while our independent assessment adjusts the vector to UI:R given the required session-riding interaction; EPSS is only 0.13% (3rd percentile) and there is no public exploit identified at time of analysis.
Earlier versions of this analysis (1)
Origin-validation bypass in the Apache Sling Security Bundle's ReferrerFilter (all versions before 1.3.2) lets an attacker satisfy the filter with forged or missing evidence instead of a true same-origin check, weakening the anti-CSRF defense for state-changing endpoints. Successful abuse requires a victim who is already authenticated to be induced into issuing a cross-origin request, so impact is limited to partial confidentiality and integrity loss and only for endpoints actually gated by ReferrerFilter; no public exploit code or confirmed in-the-wild exploitation has been identified at time of analysis. Apache has released Sling Security Bundle 1.3.2 as the fix.
RemediationAI
Vendor-released patch: upgrade Apache Sling Security Bundle to version 1.3.2, which corrects the ReferrerFilter origin-validation logic; this is the definitive fix and the version explicitly recommended by Apache in the advisory (https://lists.apache.org/thread/ohz47f6hrflsjvt9m24qz69qm5w4bwyr). If the upgrade cannot be scheduled immediately, do not treat ReferrerFilter as the sole cross-site request defense: enforce per-request CSRF tokens or strict SameSite cookie attributes so forged cross-site requests are rejected even when referrer evidence passes the filter - note that this shifts protection to the application layer and can break legitimate clients whose token handling is incomplete. Alternatively, restrict the affected administrative or state-changing endpoints to trusted networks or authenticated administrative users, accepting reduced functionality for remote clients. Because exploitation requires riding an authenticated victim session, hardening session-cookie flags and shortening session lifetimes reduces the attack window but does not remove the underlying weakness; validate any compensating control against normal Sling request flows before rolling it out, since over-restrictive referrer enforcement can block legitimate requests from proxies and privacy-stripping browsers.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
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Technical ContextAI · show details
The Apache Sling Security Bundle is an OSGi bundle in the Java-based Sling content framework that supplies authentication and request-protection services, including the ReferrerFilter. That filter implements cross-site request forgiveness by inspecting inbound Referer/Origin evidence to decide whether a state-changing request is same-origin; the flaw is an Origin Validation Error (CWE-346) in which the filter accepts evidence that is weaker than the true origin, i.e. the validation check can be satisfied by a header value that does not actually prove the request originated from the trusted site. The result is a bypass of what is effectively CSRF protection, not a memory-safety or code-execution issue, which matches the flat low CIA impacts in the 7.3 vendor vector and the CPE scope of apache_software_foundation:apache_sling_security_bundle:* for all versions prior to 1.3.2. The practical severity hinges entirely on whether ReferrerFilter is the deployment's primary defense against cross-site requests; sites that also enforce CSRF tokens or SameSite cookie policies are substantially shielded.
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
Network-reachable filter bypass with low complexity and no attacker auth, but exploiting a weakened CSRF/origin control realistically needs a victim's browser (UI:R); impacts remain Low.
Primary rating from Vendor (apache).
CVSS VectorVendor: apache
Lifecycle Timeline
2DescriptionCVE.org
A vulnerability in Apache Sling Security Bundle: the ReferrerFilter accepts weaker-than-orgin evidence.
This issue affects Apache Sling Security Bundle: before 1.3.2.
Users are recommended to upgrade to version 1.3.2, which fixes the issue.
Executive ViewAI
A weakness in the Apache Sling Security Bundle (versions before 1.3.2) allows an attacker to defeat the ReferrerFilter that many Sling-based applications rely on as their only cross-site request protection, so actions that should have been blocked can be carried out through a logged-in user's session. Only organizations running Sling deployments that use ReferrerFilter for origin validation are exposed, and the resulting business impact is limited to low-level confidentiality, integrity and availability effects. Leadership should care because this filter is frequently the sole CSRF safeguard in these deployments and a vendor fix is already available.
Apply vendor patch.
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.
EUVD-2026-85182
GHSA-h9q6-hwx8-gw7h
NVD
CVE.org
EPSS
Vulnrichment
VulDB
Exploit-DB