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CVE-2026-55784— free5GC AUSF authentication contexts can be overwritten by concurrent requests for the same SUPI

Quick assessment

Affected
free5gc free5gc
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

free5GC 是 5G 核心网的开源实现。在版本 1.4.4 及更早版本中，AUSF 组件在 中通过一个名为 的全局同步 Map 来存储每个订阅者的认证状态，该 Map 仅以 SUPI 为键。由 处理的每个请求都会创建一个 ，并执行 ，其中 会无条件地替换该 SUPI 对应的活跃上下文。攻击者若能访问 AUSF 的 SBI/N12 接口，可以针对同一目标 SUPI 发送并发的 请求，导致所有尝试共享同一个逻辑认证上下文，而 K_aut、XRES 和 EapID 会被反复覆盖。随后，针对较早挑战的有效 EAP-AK

CVSS 7.5 · High

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service
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I. Basic Information for CVE-2026-55784

Vulnerability Information
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Vulnerability Title
free5GC AUSF authentication contexts can be overwritten by concurrent requests for the same SUPI
Source: CVE Program / CVE List V5
Vulnerability Description
free5GC is an open-source implementation of the 5G core network. In version 1.4.4 and earlier, the AUSF component stores per-subscriber authentication state in a global sync.Map named AUSFContext.UePool in internal/context/context.go, keyed only by SUPI. Every request handled by internal/sbi/processor/ue_authentication.go creates an AusfUeContext, and AddAusfUeContextToPool executes ausfContext.UePool.Store(ausfUeContext.Supi, ausfUeContext), unconditionally replacing the active context for that SUPI. An attacker with access to the AUSF SBI/N12 interface can send concurrent POST /nausf-auth/v1/ue-authentications requests for the same target SUPI, causing all attempts to share one logical authentication context URL while K_aut, XRES, and EapID are repeatedly overwritten. A valid EAP-AKA' response for an earlier challenge is then checked against the latest context, causing AT_MAC verification to fail and denying authentication to the selected subscriber while the request flood continues. No fixed version is available as of this review.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
使用共享资源的并发执行不恰当同步问题(竞争条件)
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
free5gc free5gc <= 1.4.4 -

II. Public POCs for CVE-2026-55784

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III. Intelligence Information for CVE-2026-55784

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Vendor Advisories for CVE-2026-55784 (1)

Same Patch Batch · free5gc · 2026-08-28 · 3 CVEs total

CVE-2026-55068 9.3 CRITICAL free5GC: NRF nnrf-nfm lacks NF Profile input validation — enables NF Registration Poisonin
CVE-2026-55785 3.7 LOW free5GC AUSF uses non-constant-time authentication comparisons and logs XRES* in 5G-AKA

IV. Related Vulnerabilities

Same product: free5gc
Same vendor: free5gc
Same weakness: CWE-362

V. Comments for CVE-2026-55784

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