VulnerabilityPublished 9 Jan 2019Updated 9 Jun 2025

CVE-2019-5747: BusyBox · Out-of-bounds Read

Source CVE Database V5

Mentioned vulnerabilities

CVE-2018-20679

Not known to be exploited · CVSS 7.5 High.

Data as of 26 Oct 2026, 15:59 UTC

CVSS 3.1 base score

7.5High

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

EPSS: 4.6% chance of exploitation in 30 days – higher than 91% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

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

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: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
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: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 9 Jan 2019
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, 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

Affected software

Product	Affected	Fixed in
n/a n/a	Affected <=1.30.0	Fixed in–

AI-suggested

To mitigate CVE-2019-5747, European organizations should: 1) Identify and inventory all devices and systems using BusyBox DHCP components, particularly embedded systems, routers, IoT devices, and lightweight Linux distributions. 2) Apply vendor-supplied patches or firmware updates that address this vulnerability; if no official patches exist, consider upgrading BusyBox to versions beyond 1.30.0 where the issue is fixed. 3) Implement network segmentation and restrict DHCP traffic to trusted sources only, minimizing exposure to untrusted or external DHCP servers. 4) Employ DHCP snooping and filtering on network switches to prevent malicious DHCP messages from reaching vulnerable devices. 5) Monitor network traffic for anomalous DHCP messages that could indicate exploitation attempts. 6) For critical systems where patching is not immediately feasible, consider disabling DHCP client/server/relay functionality if not required or replacing vulnerable devices with secure alternatives. 7) Engage with device vendors to confirm patch availability and timelines, ensuring timely remediation. 8) Incorporate this vulnerability into vulnerability management and incident response workflows to detect and respond to potential exploitation.

Description

An issue was discovered in BusyBox through 1.30.0. An out of bounds read in udhcp components (consumed by the DHCP client, server, and/or relay) might allow a remote attacker to leak sensitive information from the stack by sending a crafted DHCP message. This is related to assurance of a 4-byte length when decoding DHCP_SUBNET. NOTE: this issue exists because of an incomplete fix for CVE-2018-20679.

Impact

For European organizations, the impact of CVE-2019-5747 can be significant, especially for those relying on embedded devices, network appliances, or IoT infrastructure that incorporate BusyBox DHCP components. Information leakage from the stack could expose sensitive data such as memory contents, configuration details, or cryptographic material, which attackers could leverage for further attacks or reconnaissance. Critical infrastructure sectors, including telecommunications, manufacturing, and energy, often deploy embedded systems with BusyBox, increasing the risk profile. Additionally, enterprises using network equipment or industrial control systems with vulnerable BusyBox versions may face increased exposure to targeted attacks. The vulnerability's remote exploitability without authentication means attackers can attempt to exploit devices simply by sending crafted DHCP messages, potentially from within the local network or via compromised upstream DHCP servers. This could lead to privacy breaches, intellectual property theft, or facilitate lateral movement within corporate networks. While no known exploits are reported in the wild, the ease of exploitation and widespread use of BusyBox in embedded devices necessitate proactive mitigation to prevent potential data leakage incidents.

CWE-125Out-of-bounds Read (opens in a new tab)
Base weaknessCWE Top 25 (2025): #8
The product reads data past the end, or before the beginning, of the intended buffer.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Architecture and Design · Language Selection
Use a language that provides appropriate memory abstractions.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (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
Overread Buffers (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 10 Jul 2025, 20:33 UTC

WeaknessesCWE-125

Technical details

References

Community reviews

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