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Unbounded Stack Buffer Overflow in SCTP Error Cause Parsing in inet_drv

High
RaimoNiskanen published GHSA-6f4f-chj5-5g97 Jun 10, 2026

Package

OTP

Affected versions

>= 17.0

Patched versions

27.3.4.13, 28.5.0.2, 29.0.2
erts (OTP)
>= 6.0
15.2.7.9, 16.4.0.2, 17.0.2

Description

Impact

The SCTP network driver, inet_drv.c, in the BEAM VM contains a stack buffer overflow bug that allows a remote, unauthenticated attacker to crash the VM by sending a single crafted SCTP ERROR chunk, after successfully creating an SCTP association to a listening SCTP port.

In a hypothetical VM, built without stack protection, which is not default, the overflow should not have the potential to achieve Remote Code Execution since the attacker can only write 16-bit values interleaved with a fixed tag hence not a controlled return address. For a VM with standard build stack protection, there should be no way to skip over the stack canary and corrupt the stack without triggering the stack protection and crash the VM process.

A crafted SCTP ERROR chunk may also leak bits and pieces of Erlang VM memory into the received error packet in the Erlang process. Such data, conceptually, is already allowed to read by the system user that runs the Erlang VM, but it would probably be against the application's intention, so the harm caused by such a data leak should be limited.

Systems are affected when SCTP support is enabled, a listening SCTP socket is opened via gen_sctp with the default inet backend, and the listening port is reachable from the attacker's network.

Workarounds

No workarounds besides not opening an SCTP listening socket on a network an attacker can reach.

Not running a VM built without stack protection would avoid the faint possibility of Remote Code Execution or continuing to run with a corrupted stack.

Affected/Unaffected Versions

A version larger than or equal to one of the listed patched versions is unaffected; otherwise, a version that satisfies an expression listed under affected versions is affected, and if it does not, it is unaffected.

The documentation of the OTP version scheme describes how versions should be compared. Note that versions used prior to OTP 17.0, when the new OTP version scheme was introduced, are never listed since it is not well defined how to compare those versions.

In the case of this vulnerability, versions prior to OTP 17.0 are also affected — the vulnerable code has existed unchanged since SCTP support was introduced . Windows builds are unaffected because SCTP is not supported on Windows.

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v4 base metrics

Exploitability Metrics
Attack Vector Network
Attack Complexity Low
Attack Requirements None
Privileges Required None
User interaction None
Vulnerable System Impact Metrics
Confidentiality Low
Integrity None
Availability High
Subsequent System Impact Metrics
Confidentiality None
Integrity None
Availability None

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N

CVE ID

CVE-2026-49759

Weaknesses

Stack-based Buffer Overflow

A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). Learn more on MITRE.

Credits