VulnerabilityPublished 8 Aug 2024Updated 3 Nov 2025

CVE-2024-43167: Red Hat Enterprise Linux 6 · NULL Pointer Dereference

Affects Red Hat Enterprise Linux 6Source CVE Database V5

Not known to be exploited · CVSS 2.8 Low.

Data as of 26 Oct 2026, 08:30 UTC

CVSS 3.1 base score

2.8Low

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 32% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

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

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

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
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: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
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: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 8 Aug 2024
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 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

AI-suggested

Organizations should first verify if their Red Hat Enterprise Linux 6 systems utilize the Unbound DNS resolver and whether the vulnerable API functions are exposed or used in their environment. Since the vulnerability requires local access and specific API call sequences, restricting access to systems and limiting user privileges can reduce risk. Applying any available patches or updates from Red Hat is recommended once released. In the absence of patches, consider implementing monitoring to detect abnormal Unbound process crashes and automate service restarts to minimize downtime. Additionally, review application usage patterns to avoid invoking the vulnerable API sequences. For critical DNS infrastructure, consider upgrading to a supported Red Hat Enterprise Linux version or alternative DNS resolver implementations that do not exhibit this behavior. Engage with Red Hat support for tailored guidance and to confirm if backported fixes or workarounds exist.

Description

DISPUTE NOTE: this issue does not pose a security risk as it (according to analysis by the original software developer, NLnet Labs) falls within the expected functionality and security controls of the application. Red Hat has made a claim that there is a security risk within Red Hat products. NLnet Labs has no further information about the claim, and suggests that affected Red Hat customers refer to available Red Hat documentation or support channels. ORIGINAL DESCRIPTION: A NULL pointer dereference flaw was found in the ub_ctx_set_fwd function in Unbound. This issue could allow an attacker who can invoke specific sequences of API calls to cause a segmentation fault. When certain API functions such as ub_ctx_set_fwd and ub_ctx_resolvconf are called in a particular order, the program attempts to read from a NULL pointer, leading to a crash. This issue can result in a denial of service by causing the application to terminate unexpectedly.

Impact

The primary impact of CVE-2024-43167 is a denial of service condition caused by the unexpected termination of the Unbound DNS resolver process. For organizations relying on Red Hat Enterprise Linux 6 systems running Unbound, this could lead to temporary DNS resolution failures, potentially disrupting network services and applications dependent on DNS. However, the impact is limited as exploitation requires local access and user interaction, reducing the likelihood of widespread or remote attacks. There is no risk of data leakage, privilege escalation, or persistent compromise. The denial of service could affect availability of DNS services on critical infrastructure, but given the age of the affected product and the limited scope, the overall risk to large-scale operations is low. Organizations with high availability DNS requirements should consider the potential for service interruption and plan accordingly.

References

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 28 Feb 2026, 06:26 UTC

Technical details

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