VulnerabilityPublished 23 Mar 2026

CVE-2026-33281: ellanetworks core · Improper Validation of Array Index

Affects ellanetworks coreSource CVE Database V5

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Not known to be exploited · CVSS 6.5 Medium : upgrade to 1.6.0 when convenient.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 35% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 1.6.0

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 23 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade core and ellanetworks/core to 1.6.0.

Affected software

Product	Affected	Fixed in
ellanetworkscore	Affected <1.6.0	Fixed in 1.6.0
GitHubellanetworks/core`pkg:github/ellanetworks/core`Other threats	Affected <1.6.0	Fixed in 1.6.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Organizations using Ella Core versions prior to 1.6.0 should prioritize upgrading to version 1.6.0 or later, where the vulnerability is patched with proper PDU Session ID validation. In environments where immediate upgrade is not feasible, network operators should implement strict filtering and validation of NGAP messages at the network edge or firewall to block malformed or out-of-range PDU Session IDs. Monitoring NGAP traffic for anomalous or unexpected session IDs can help detect attempted exploitation. Additionally, deploying redundancy and failover mechanisms for the 5G core can minimize service disruption in case of a crash. Network segmentation and limiting exposure of the NGAP interface to trusted network segments can reduce the attack surface. Regular security assessments and penetration testing focused on signaling protocols can help identify similar vulnerabilities proactively. Finally, maintaining up-to-date incident response plans for 5G core outages will improve resilience against denial-of-service attacks.

Description

Ella Core is a 5G core designed for private networks. Versions prior to 1.6.0 panic when processing NGAP messages with invalid PDU Session IDs outside of 1-15. An attacker able to send crafted NGAP messages to Ella Core can crash the process, causing service disruption for all connected subscribers. No authentication is required. Version 1.6.0 added PDU Session ID validations during NGAP message handling.

Impact

The primary impact of this vulnerability is a denial-of-service condition affecting the availability of the 5G core network services managed by Ella Core. Since the core process crashes upon receiving malformed NGAP messages, all subscribers connected to the affected core instance will experience service disruption, potentially leading to loss of connectivity, dropped sessions, and degraded network performance. This can affect private 5G network operators relying on Ella Core for mission-critical communications, industrial automation, or enterprise connectivity. The impact on confidentiality and integrity is negligible, as the vulnerability does not allow data leakage or unauthorized modification. However, the ease of exploitation—requiring no authentication and only crafted NGAP messages—makes it a significant risk for service availability. Organizations operating private 5G networks with affected versions may face operational downtime, customer dissatisfaction, and potential financial losses. The lack of known exploits in the wild reduces immediate risk but does not eliminate the threat, especially as attackers could develop exploits given the public disclosure.

CWE-129Improper Validation of Array Index (opens in a new tab)
Variant weaknessLikelihood of exploit: HighOWASP Top 10 A05:2025: Injection (opens in a new tab)
The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array.
Architecture and Design · Input Validation
Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks…
Requirements · Language Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
Injection Prevention (opens in a new tab)
SQL Injection Prevention (opens in a new tab)
Injection Prevention in Java (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
Attack patterns
Overflow Buffers (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

github.com/ellanetworks/core/security/advisories/GHSA-q669-4gmv-g8mf (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 24 Mar 2026, 00:15 UTC

WeaknessesCWE-129

Technical details

References

Community reviews

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