VulnerabilityPublished 5 Apr 2024Updated 4 Dec 2024

CVE-2024-31852: LLVM before 18.1.3 generates code

Source CVE Database V5

Not known to be exploited · CVSS 5.9 Medium.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

5.9Medium

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

EPSS: 0.9% chance of exploitation in 30 days – higher than 62% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Network
Attack Complexity: High
Privileges Required: None
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: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
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: 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 5 Apr 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 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

AI-suggested

To mitigate CVE-2024-31852, organizations should upgrade LLVM to version 18.1.3 or later, where the issue is resolved. Comprehensive testing and fuzzing of ARM-targeted binaries should be enhanced to detect miscompilations that could cause crashes. Incorporate static and dynamic analysis tools to identify control flow anomalies in compiled code. Avoid deploying binaries compiled with vulnerable LLVM versions in production environments, especially for critical systems. For legacy systems where recompilation is not immediately feasible, implement runtime monitoring to detect abnormal crashes and enable rapid incident response. Developers should review build pipelines to ensure no outdated LLVM versions are used inadvertently. Additionally, consider employing compiler verification tools or alternative compilers for ARM targets as a temporary measure. Maintain awareness of LLVM updates and security advisories to promptly address similar future issues.

Description

LLVM before 18.1.3 generates code in which the LR register can be overwritten without data being saved to the stack, and thus there can sometimes be an exploitable error in the flow of control. This affects the ARM backend and can be demonstrated with Clang. NOTE: the vendor perspective is "we don't have strong objections for a CVE to be created ... It does seem that the likelihood of this miscompile enabling an exploit remains very low, because the miscompile resulting in this JOP gadget is such that the function is most likely to crash on most valid inputs to the function. So, if this function is covered by any testing, the miscompile is most likely to be discovered before the binary is shipped to production."

Impact

The primary impact of CVE-2024-31852 is on the availability of software compiled with affected LLVM versions targeting ARM architectures. Miscompiled binaries may crash unexpectedly due to overwritten LR registers, leading to denial of service conditions. While confidentiality and integrity are not directly compromised, the presence of a JOP gadget could theoretically be leveraged in complex exploit chains, although this is considered unlikely. Organizations relying on LLVM for ARM development, especially those deploying critical embedded systems, IoT devices, or mobile applications, may face stability and reliability issues if vulnerable binaries are shipped to production. The vulnerability could disrupt services, cause system outages, or require emergency patches and recompilation efforts. The lack of known exploits and the difficulty of exploitation reduce immediate risk, but the potential for latent instability necessitates prompt remediation. The impact is more pronounced in sectors with high ARM usage such as telecommunications, automotive, consumer electronics, and cloud edge computing.

Summary

CVE-2024-31852 is a compiler vulnerability found in LLVM versions before 18.1.3 that affects the ARM backend code generation. Specifically, the compiler may generate code where the Link Register (LR), which stores the return address for function calls, is overwritten without being saved onto the stack. This improper handling can lead to control flow errors, potentially allowing an attacker to craft a Jump-Oriented Programming (JOP) gadget. JOP gadgets can be used in advanced exploitation techniques to hijack program execution flow. However, the vendor notes that the likelihood of successful exploitation is low because the miscompiled function usually crashes on valid inputs, making the issue detectable during normal testing before deployment. This vulnerability does not affect confidentiality or integrity directly but can cause denial of service due to crashes (availability impact). The vulnerability requires no privileges or user interaction and can be exploited remotely if the compiled binary is exposed. No known exploits have been reported in the wild. The vulnerability is relevant to organizations compiling software for ARM architectures using affected LLVM versions. The CVSS v3.1 score is 5.9 (medium), reflecting network attack vector, high attack complexity, no privileges required, no user interaction, unchanged scope, no confidentiality or integrity impact, but high availability impact.

References

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