EUVD-2026-44318
GHSA-rwpj-48r2-w395
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessAuthenticate to AD FS endpoint
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DeliverySend crafted federation request
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ExploitTrigger out-of-bounds read in parser
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ExecutionLeak adjacent process memory
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ImpactHarvest disclosed sensitive data
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, read limits
MITRE ATT&CK
1 technique across 1 tactic: Collection The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | Exploitation requires the attacker to reach a Microsoft AD FS network endpoint and to hold at least low-level authentication to that service (CVSS PR:L), so this is not an unauthenticated internet-wide risk; a valid AD FS credential or authenticated session is the concrete prerequisite. No user interaction is needed (UI:N) and attack complexity is low (AC:L), so once authenticated the read can be triggered directly over the network. Limiting factors: the requirement for prior authentication, the need for network access to the federation endpoints, and an unresolved platform question - the CPE points only to Windows 11 26H1 while the description names the AD FS server role, so the exact vulnerable deployment/build must be confirmed with Microsoft. |
| Impact | Signals are moderate and somewhat mixed. CVSS 3.1 is 7.1 (High) with a network vector, low attack complexity, and no user interaction, but it requires low privileges (PR:L), meaning the attacker must already be authenticated to AD FS at some level - this meaningfully narrows the exploit population versus a pre-auth flaw. Impact is confidentiality-only high (C:H) plus low availability (A:L), with no integrity impact, so this is a data-disclosure and possible minor-disruption issue rather than code execution. No EPSS score was provided, there is no KEV listing (not actively exploited), and no POC is indicated, so real-world urgency is currently lower than the raw 7.1 suggests - though AD FS's role as an identity broker raises the stakes of any memory leak. A notable data conflict: the description scopes this to AD FS while the single CPE names Windows 11 26H1 (a client OS that does not normally run the AD FS server role), so the true affected surface should be confirmed with the vendor before prioritization. |
| Exploit ScenarioDerived | An attacker who holds a low-privilege authenticated foothold against the AD FS service sends specially crafted requests to a vulnerable endpoint, triggering the out-of-bounds read so the service returns adjacent process memory in its response. Over repeated requests the attacker harvests leaked fragments that may contain sensitive authentication material or configuration data. No public exploit is identified at time of analysis, and the low attack complexity (AC:L) means reliable triggering is plausible once the flaw is understood. |
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Alert meAnalysisAIv1 – Jul 14, 2026
Information disclosure in Microsoft Active Directory Federation Services (AD FS) lets an authenticated, network-based attacker read memory outside intended bounds and leak sensitive data, per Microsoft's own report of the flaw (tracked in MSRC as CVE-2026-58529). The CVSS 3.1 vector (AV:N/AC:L/PR:L/UI:N, C:H) indicates low-privilege remote exploitation with high confidentiality impact; there is no public exploit identified at time of analysis and it is not on CISA KEV. A vendor patch is available. Note a data discrepancy: the flaw is described as AD FS (a server role) yet the only CPE lists the Windows 11 version 26H1 client - verify affected platforms with Microsoft.
RemediationAI
Patch available per vendor advisory - apply the Microsoft security update for CVE-2026-58529 as listed in the MSRC update guide (https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58529); the input confirms a fix is available but does not enumerate an exact patched build number, so pull the specific KB/version from that advisory for your platform. Because exploitation requires an authenticated (PR:L) network position, interim compensating controls include restricting network reachability of AD FS endpoints (for example, placing the AD FS/WAP proxy behind conditional access and limiting exposure of the federation and token endpoints to trusted networks or VPN), enforcing least-privilege on accounts that can authenticate to AD FS, and increasing monitoring of AD FS request/audit logs for anomalous access - with the trade-off that tightening endpoint exposure can disrupt legitimate external federation/SSO for remote users. These controls reduce but do not eliminate risk; patching is the only complete fix.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
AD FS is Microsoft's on-premises identity federation service that issues security tokens (SAML/WS-Federation/OAuth) to enable single sign-on between an organization's Active Directory and external/relying-party applications, typically exposed over HTTPS network endpoints. The root cause is CWE-125, an out-of-bounds read, where code reads memory past the end (or before the start) of an allocated buffer - here likely during parsing of attacker-influenced request/token data - returning adjacent process memory contents. Microsoft's tagging also references 'Buffer Overflow,' consistent with a boundary-checking defect in a parser. Because AD FS handles authentication material, leaked memory could plausibly expose tokens, keys, or other secrets, which aligns with the C:H rating.
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Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:L
Network-reachable AD FS endpoint (AV:N) exploitable with an authenticated low-privilege session (PR:L) and no user interaction; out-of-bounds read discloses sensitive memory (C:H) with possible service instability (A:L), no integrity impact.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
DescriptionCVE.org
Out-of-bounds read in Active Directory Federation Services (AD FS) allows an authorized attacker to disclose information over a network.
Executive ViewAI
Microsoft Active Directory Federation Services contains an information disclosure vulnerability (CVE-2026-58529, CVSS 7.1) that allows authenticated attackers to extract sensitive data from system memory. AD FS is critical to enterprise identity and access management; successful exploitation could expose credentials, federation metadata, or other sensitive configuration data that attackers could leverage for lateral movement or further compromise. Organizations should prioritize patching this vulnerability across their identity infrastructure.
Apply vendor patch.
Threat Intelligence Overview
NVD
CVE.org
EPSS
Vulnrichment
VulDB
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
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.
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