Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Lifecycle Timeline
5DescriptionCVE.org
A vulnerability was determined in Open5GS up to 2.7.7. This affects the function gsm_handle_pdu_session_modification_qos_flow_descriptions of the file src/smf/gsm-handler.c of the component SMF. Executing a manipulation of the argument n1SmMsg can lead to denial of service. The attack may be launched remotely. The exploit has been publicly disclosed and may be utilized. The pull request to fix this issue awaits acceptance.
AnalysisAI
Denial of service in Open5GS SMF (Session Management Function) via crafted PDU Session Modification messages allows remote authenticated attackers to trigger unvalidated parameter processing in gsm_handle_pdu_session_modification_qos_flow_descriptions(), causing service disruption. The vulnerability stems from insufficient pre-validation of QoS flow parameter identifiers and bitrate units before state mutation, potentially leaving the SMF in an inconsistent state. Publicly available exploit code exists, and a fix awaits upstream acceptance in PR #4513.
Technical ContextAI
Open5GS is a 5G core network implementation. The SMF (Session Management Function) handles PDU Session Modification Requests from user equipment (UE), which include QoS (Quality of Service) flow descriptions with parameters such as 5QI (5G QoS Identifier), GFBR (Guaranteed Flow Bit Rate), and MFBR (Maximum Flow Bit Rate). The vulnerable function gsm_handle_pdu_session_modification_qos_flow_descriptions() in src/smf/gsm-handler.c processes the n1SmMsg argument containing these flow descriptions. The root cause (CWE-404: Improper Resource Validation) manifests as missing pre-validation of QoS parameter identifiers against spec-defined values (TS 24.501 §9.11.4.12) and bitrate unit validation against the range OGS_NAS_BR_UNIT_1K to OGS_NAS_BR_UNIT_256P (TS 24.501 §9.11.4.13). Without pre-validation, malformed parameters cause premature exit mid-loop after partial state mutations, leaving the SMF's bitrate table in an inconsistent state that can only be recovered by detach/re-attach cycles.
RemediationAI
Apply the fix from GitHub PR #4513 (https://github.com/open5gs/open5gs/pull/4513), which implements a two-pass validation strategy: Pass 1 pre-validates all QoS flow parameter identifiers (5QI, GFBR uplink/downlink, MFBR uplink/downlink) and bitrate units against 3GPP TS 24.501 spec ranges before any state mutation occurs; Pass 2 applies validated descriptions without further checks. Exact patched version not independently confirmed from provided data, but the upstream PR provides the complete fix. Interim workarounds pending patch deployment: (1) restrict PDU Session Modification message processing to trusted UE sources only via network-layer firewall rules (trade-off: may block legitimate roaming partners); (2) implement rate-limiting on PDU Session Modification requests per UE (trade-off: may delay legitimate QoS adjustments); (3) monitor SMF logs for 'Invalid bitrate unit' or 'Unknown qos_flow parameter identifier' errors and isolate offending UE sessions (trade-off: requires operational overhead and may impact user experience). Most robust immediate mitigation is to pull and build from the PR #4513 branch directly if stable release is not available.
open5gs v2.6.4 is vulnerable to Buffer Overflow. Rated critical severity (CVSS 9.8), this vulnerability is remotely expl
Open5GS v2.6.4 is vulnerable to Buffer Overflow. Rated critical severity (CVSS 9.8), this vulnerability is remotely expl
A request-validation issue was discovered in Open5GS 2.1.3 through 2.2.x before 2.2.1. Rated critical severity (CVSS 9.8
Open5GS 2.1.3 listens on 0.0.0.0:3000 and has a default password of 1423 for the admin account. Rated high severity (CVS
Open5GS MME versions <= 2.6.4 contain a reachable assertion in the `Uplink NAS Transport` packet handler. Rated high sev
Open5GS MME version <= 2.6.4 contains an assertion that can be remotely triggered via a malformed ASN.1 packet over the
Open5GS MME versions <= 2.6.4 contain an assertion that can be remotely triggered via a malformed ASN.1 packet over the
Open5GS MME versions <= 2.6.4 contains an assertion that can be remotely triggered via a malformed ASN.1 packet over the
Open5GS MME versions <= 2.6.4 contains an assertion that can be remotely triggered via a malformed ASN.1 packet over the
Open5GS MME versions <= 2.6.4 contain an assertion that can be remotely triggered via a malformed ASN.1 packet over the
Open5GS MME versions <= 2.6.4 contain an assertion that can be remotely triggered via a malformed ASN.1 packet over the
Open5GS MME versions <= 2.6.4 contains an assertion that can be remotely triggered via a malformed ASN.1 packet over the
Same weakness CWE-404 – Improper Resource Shutdown or Release
View allSame technique Denial Of Service
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-29050
GHSA-x779-6vcw-95p6