Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessReach SMF on UDP 8805 (PFCP N4)
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DeliverySend crafted Session Report Request
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ExploitShort all-flags Volume Measurement IE
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ExecutionParser reads past IE buffer
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ImpactCrash SMF, control-plane DoS
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 | Requires the attacker to be able to send UDP packets to the SMF's PFCP interface on port 8805 - specifically a PFCP Session Report Request carrying a Volume Measurement IE whose flag bits are all set while the IE body is too short to contain the declared fields, causing the parser to read beyond the IE buffer. No authentication is required (PR:N) and default configurations of Open5GS through 2.8.0 are affected. The key LIMITING factor is network exposure of the PFCP N4 interface: in standard 5G core architecture this interface sits on an internal control-plane network between SMF and UPF and is not intended to be internet-reachable, so successful exploitation generally presupposes a foothold on, or a routing path into, the core network segment. Impact is limited to SMF crash/denial of service; the over-read data is not disclosed to the attacker. |
| Impact | This is a medium-severity (CVSS 4.0 base 6.9) heap out-of-bounds read with availability-only impact (VA:L; VC:N/VI:N). The CVSS vector (AV:N/AC:L/AT:N/PR:N/UI:N) indicates a network-reachable, low-complexity, unauthenticated trigger, which raises concern, but the real-world risk is materially tempered by two factors the raw score understates. First, the affected interface is the PFCP N4 interface on UDP 8805 between the SMF and UPF - in correct 5G core deployments this is an internal control-plane segment, not an internet-facing service, so 'network vector' here usually means 'reachable from within the core network' rather than 'reachable from the public internet'; defenders should treat AV:N with that caveat. Second, the impact is a crash/DoS of the SMF, not code execution or data theft - the vendor's VC:N correctly reflects that the up-to-48-byte over-read is not returned to the attacker, so despite the 'Information Disclosure' tag this is functionally a denial-of-service against the 5G control plane rather than a confidentiality breach. No EPSS score was supplied and the CVE is NOT in CISA KEV; no public exploit was provided in the intelligence. Net assessment: a legitimate patch-worthy control-plane DoS, but not an emergency mass-exploitation threat - prioritize for core-network operators but below internet-exposed RCE-class issues. |
| Exploit ScenarioDerived | An attacker with access to the 5G core network segment (or any path to the SMF's PFCP N4 interface) sends a single crafted PFCP Session Report Request to UDP port 8805 containing a Volume Measurement IE that sets all length flags but is truncated. The SMF's ogs_pfcp_parse_volume_measurement() reads past the IE buffer by up to 48 bytes, which can crash the SMF and disrupt session management across the core. No public exploit code was identified in the provided intelligence, though the vendor advisory and precise code location make reproduction straightforward. |
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Alert meAnalysisAIv1 – Oct 09, 2026
Open5GS through 2.8.0 contains a heap out-of-bounds read that lets remote unauthenticated attackers crash the SMF by sending a crafted PFCP Session Report Request to UDP port 8805 carrying a Volume Measurement IE whose flag bits are all set while the IE body is too short to hold the declared fields. The parser in lib/pfcp/types.c walks past the end of the IE buffer by as much as 48 bytes, producing availability-only impact (CVSS 4.0 base 6.9, CWE-125); the over-read bytes are not returned to the attacker, so this is a denial-of-service condition rather than a data leak. No public exploit code has been identified at time of analysis, and practical exploitation presupposes that the attacker can reach the internal N4/PFCP control-plane interface between SMF and UPF, which is not intended to be internet-facing.
RemediationAI
Upstream fix available (PR/commit); released patched version not independently confirmed - apply the upstream commit 88e64fc1f87e0d321364b3bb710ef6a8f274e568 (or any build containing it, i.e. a release subsequent to 2.8.0) which adds OCTET length checks in ogs_pfcp_parse_volume_measurement and its sibling PFCP parsers; review the advisory at https://github.com/open5gs/open5gs/security/advisories/GHSA-37c3-hv4f-688p before rolling out. If upgrading cannot be done immediately, the highest-value compensating control is network containment of the PFCP N4 interface: restrict inbound UDP/8805 on the SMF so that only the legitimate UPF peer addresses can reach it (host firewall, iptables/nftables rules or core-network segmentation), noting the trade-off that overly strict filtering breaks UPF association, multi-UPF scaling and vendor interoperability and must be kept in sync with the UPF address plan. Because the failure mode is a process crash rather than memory corruption with code execution, running the SMF under a supervised service manager with automatic restart (for example systemd Restart=always with a rate limit) reduces the outage window, but this only masks the bug, adds restart churn, and can drop in-flight session state, so it is a stopgap only. Deep packet inspection or a PFCP-aware filter that rejects Volume Measurement IEs whose declared length is shorter than the fields implied by their flag byte can be used in environments where an N4 mediation layer already exists, though it introduces latency and a new failure point on the control plane.
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
PFCP (Packet Forwarding Control Protocol) is the 3GPP control protocol carried over UDP/8805 on the N4 reference point between the Session Management Function (SMF) and the User Plane Function (UPF) in 5G core deployments. PFCP messages are built from Information Elements encoded as type-length-value structures; a Volume Measurement IE begins with a one-byte flags field in which each bit signals the presence of an optional 8-byte measurement field (total, uplink and downlink volume counters, and total, uplink and downlink packet counters). The vulnerable function ogs_pfcp_parse_volume_measurement() in lib/pfcp/types.c (lines 581-635 in the v2.8.0 tree) trusted those flag bits and advanced its read cursor for every field whose bit was set without first verifying that the IE's declared length actually covered the field, so an IE that advertises all flags but supplies a truncated body caused the pointer to run up to 48 bytes past the buffer (six unset-length 8-byte fields), reading freed or adjacent heap memory and potentially terminating the SMF process. This is a classic CWE-125 out-of-bounds read caused by missing length validation on variable-length, flag-driven TLV parsing. The upstream fix commit 88e64fc1f87e0d321364b3bb710ef6a8f274e568 adds explicit 'size + sizeof(field) > octet->len' guards before each field read, and applies the same defensive pattern to three sibling parsers in the same file (ogs_pfcp_parse_sdf_filter, ogs_pfcp_parse_volume, and ogs_pfcp_parse_dropped_dl_traffic_threshold), indicating a systematic hardening of PFCP IE parsing rather than a single one-off correction.
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Severity by source
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
Unauthenticated network-reachable PFCP parser triggered by a single malformed packet (AV:N/AC:L/PR:N/UI:N); over-read data is never returned so C:N/I:N, and impact is an SMF crash giving partial availability loss (A:L).
Primary rating from Vendor (VulnCheck).
CVSS VectorVendor: VulnCheck
DescriptionCVE.org
Open5GS through 2.8.0 contains a heap out-of-bounds read vulnerability in ogs_pfcp_parse_volume_measurement() in lib/pfcp/types.c that allows remote unauthenticated attackers to read past IE buffers. Attackers can send a PFCP Session Report Request to the SMF on UDP port 8805 with a short, all-flags Volume Measurement IE, reading up to 48 bytes and potentially crashing the SMF.
Threat Intelligence Overview
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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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
EUVD-2026-95793
GHSA-337v-466h-8gh6
NVD
CVE.org
EPSS
Vulnrichment
Exploit-DB