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UERANSIM CVE-2026-100892

| EUVDEUVD-2026-88056 MEDIUM
Buffer Overflow (CWE-119)
2026-09-28 VulDB GHSA-mqvr-mhj9-rgx9
5.5
CVSS 4.0 · Vendor: VulDB
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Connect to gNB as UE peer
  2. Delivery
    Craft malformed dedicatedNASMessage in RRC
  3. Exploit
    Send ULInformationTransfer to nr-gnb
  4. Execution
    Trigger memory corruption in handler.cpp
  5. Impact
    Crash gNB simulator (DoS)

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, buffer size validation
MITRE ATT&CK

2 techniques across 2 tactics: Execution, Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires network reachability to a running UERANSIM nr-gnb instance (version up to 3.3.0) and the ability to send RRC signaling to it as a UE peer, then supplying a manipulated dedicatedNASMessage in an ULInformationTransfer message. Per the CVSS vector (PR:N/UI:N) no authentication or user interaction is required, and the attack is remote (AV:N) with low complexity (AC:L). Limiting factors: the target is an open-source 5G simulator typically confined to research/test networks rather than internet-exposed production, and the attacker must be able to reach the gNB's signaling interface; demonstrated impact is availability loss (crash) only, not confidentiality or integrity.

Impact

This is a real but bounded issue best characterized as a remote crash/DoS rather than a critical RCE. The vendor (VulDB) CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L) scores impact as availability-only (VA:L) with no confidentiality or integrity effect, which is notably conservative for a CWE-119 memory-corruption bug - memory corruption CAN sometimes escalate beyond a crash, but neither the description nor the vendor claims code execution, so the demonstrated impact is a low-severity availability loss. Exploitation status: publicly available exploit code exists (POC gist), reflected in the E:P (Proof-of-Concept) exploit-maturity flag; this is NOT the same as active exploitation - there is no CISA KEV listing and no EPSS score in the input, so exploitation is possible-but-unproven-in-the-wild. The attack path (a malicious/rogue UE sending a crafted RRC ULInformationTransfer to the gNB) is network-reachable and low-complexity, but the affected product is a research/test simulator, not production carrier infrastructure, which sharply limits real-world blast radius. Net: modest priority - patch or upgrade in lab/CI environments running UERANSIM, but this is not an internet-scale emergency.

Exploit ScenarioDerived

An attacker positioned as (or spoofing) a connected UE on the radio/network interface of a UERANSIM nr-gnb instance sends a crafted RRC message containing a malformed dedicatedNASMessage argument, which is mishandled in ULInformationTransfer (src/gnb/rrc/handler.cpp) and triggers memory corruption. The result is corruption/crash of the gNB simulator process, disrupting the 5G test environment. A public proof-of-concept exploit is available on GitHub (gist), lowering the effort to reproduce.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.6% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 28, 2026

Remote denial of service in aligungr UERANSIM up to 3.3.0 allows an unauthenticated network attacker who can reach the nr-gnb signaling interface to trigger memory corruption by sending a crafted dedicatedNASMessage in an RRC ULInformationTransfer message. The assessed impact is limited to availability loss (crash) rather than code execution, confidentiality, or integrity compromise, and the affected software is an open-source 5G simulator typically deployed in research or test networks. Publicly available exploit code exists, and the vendor was reportedly contacted but did not respond.

RemediationAI

No vendor-released patch identified at time of analysis; the vendor was contacted and did not respond, so no fixed UERANSIM version can be confirmed from the available data. Until an official patch is released, restrict access to the nr-gnb RRC/NAS signaling interface to trusted UEs on an isolated lab VLAN or firewall it from untrusted networks, and consider disabling nr-gnb when the gNB simulator is not actively needed. For maintainers who can modify UERANSIM, add strict length validation and bounds checking for the dedicatedNASMessage argument in src/gnb/rrc/handler.cpp before any copy or memory operation; trade-offs are reduced simulation testing flexibility and the need to track a custom fork. Monitor gNB logs for crashes or malformed ULInformationTransfer messages, and review the VulDB advisory at https://vuldb.com/vuln/410842 and exploit reference at https://gist.github.com/centauruszzz/c69a6bd152f45d9ca8db981f7da34bed for updates. If a patched release later appears, upgrade to that exact version after confirming it fixes this CVE.

Affected VersionsENISA

UERANSIM 3.2
UERANSIM 3.1
UERANSIM 3.0
UERANSIM 3.3.0

Affected Packages

euvd ueransim no fix

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

UERANSIM is an open-source 5G SA simulator implementing UE and gNB (nr-gnb) functions, including RRC signaling and NAS transport. The flaw resides in src/gnb/rrc/handler.cpp in ULInformationTransfer, where the dedicatedNASMessage argument is processed without sufficient validation, leading to CWE-119 memory corruption/buffer overflow. The CPE cpe:2.3:a:aligungr:ueransim:*:*:*:*:*:*:*:* identifies aligungr UERANSIM, with the description bounding affected releases to 3.3.0 and earlier. Exploitation requires sending RRC messages as a UE peer; per the assessed CVSS vector PR:N/UI:N, no authentication or user interaction is needed, and the demonstrated consequence is a remote crash/DoS.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (VulDB) PRIMARY 5.5 MEDIUM
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
vuln.today AI 5.3 MEDIUM

Remote unauthenticated crafted RRC message with no interaction (AV:N/AC:L/PR:N/UI:N); impact limited to a simulator crash (A:L), no confidentiality or integrity effect per vendor VA:L-only assessment.

3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

Primary rating from Vendor (VulDB).

CVSS VectorVendor: VulDB

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Vulnerable system: Confidentiality
None
Vulnerable system: Integrity
None
Vulnerable system: Availability
Low
Subsequent system: Confidentiality
None
Subsequent system: Integrity
None
Subsequent system: Availability
None

Lifecycle Timeline

2
CVSS changed
Sep 28, 2026 - 01:22 NVD
6.9 (MEDIUM) 5.5 (MEDIUM)
CVE Published
Sep 28, 2026 - 00:30 cve.org
MEDIUM 6.9

DescriptionCVE.org

A vulnerability was found in aligungr UERANSIM up to 3.3.0. This affects the function ULInformationTransfer of the file src/gnb/rrc/handler.cpp of the component nr-gnb. Performing a manipulation of the argument dedicatedNASMessage results in memory corruption. The attack can be initiated remotely. The exploit has been made public and could be used. The vendor was contacted early about this disclosure but did not respond in any way.

Threat Intelligence Overview

EPSS Score
0.6%
Top 53% exploitable
Prevalence
Low
open-source 5G RAN/UE simulator for research and lab testing, not production
Exploit
POC
Public exploit code exists
Data Quality
6 sources
Confidence: High
EUVD NVD CVE.org EPSS Vulnrichment GitHub 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.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC Yes
EPSS 0.6%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation
Poc
System Exposure· derived
Open
Automatable
Yes
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

49
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +28
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

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.

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