Answer in brief
CVE-2026-55784 records a High severity (CVSS 7.5) vulnerability in free5GC AUSF authentication contexts can be overwritten by concurrent requests for the same SUPI. The current sources do not mark it as known exploited. The current feed maps free5gc/free5gc (generic), github.com/free5gc/ausf (go), github.com/free5gc/ausf (go). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps free5gc/free5gc (generic), github.com/free5gc/ausf (go), github.com/free5gc/ausf (go). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| free5gc/free5gcgeneric | <= 1.4.4 | Not reported |
| github.com/free5gc/ausfgo | <=1.4.4 | Not reported |
| github.com/free5gc/ausfgo | >=0 | Not reported |
Published upstream
Aug 28, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 28, 2026
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.
Quoted source text, attributed separately from HOL analysis.