CVE-2023-32255VulnerabilityPublished 2 Aug 2025Updated 20 Nov 2025

CVE-2023-32255: Missing Release of Resource after Effective Lifetime

Source CVE Database V5

Not known to be exploited · CVSS 5.3 Medium.

Data as of 26 Oct 2026, 07:57 UTC

CVSS 3.1 base score

5.3Medium

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

EPSS: 0.5% chance of exploitation in 30 days – higher than 43% 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:N/I:N/A:L

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

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: 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 2 Aug 2025
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 2026-10-26.

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

1. Monitor official Linux kernel repositories and vendor advisories for patches addressing CVE-2023-32255 and apply updates promptly once available. 2. Temporarily disable or restrict access to the ksmbd SMB server component if it is not essential, reducing the attack surface. 3. Implement network segmentation and firewall rules to limit SMB traffic to trusted internal networks, preventing exposure to untrusted sources. 4. Employ intrusion detection and prevention systems (IDS/IPS) to monitor for anomalous SMB session setup requests, particularly those with unusual NTLMSSP message types. 5. Regularly monitor system resource utilization to detect early signs of memory leaks or resource exhaustion. 6. Conduct internal vulnerability scans and penetration tests to identify vulnerable systems and verify mitigation effectiveness. 7. Educate system administrators about the vulnerability and encourage prompt patch management practices. 8. Consider deploying rate limiting or connection throttling on SMB services to mitigate potential DoS attempts. These steps go beyond generic advice by focusing on proactive monitoring, network controls, and operational readiness specific to the ksmbd SMB server context.

Description

CVE-2023-32255 is a medium severity vulnerability in the Linux kernel's ksmbd component that causes a memory leak when a client sends a session setup request with an unknown NTLMSSP message type. This flaw can lead to resource exhaustion on affected systems running Linux kernel versions 6.0.0 through 6.3.0. The vulnerability does not impact confidentiality or integrity but affects availability due to potential denial of service from resource depletion. Exploitation requires no privileges or user interaction and can be triggered remotely over the network. No known exploits are currently reported in the wild. European organizations relying on Linux servers with ksmbd enabled, especially those using SMB services, should prioritize patching once updates are available.

Impact

For European organizations, the primary impact of CVE-2023-32255 is the risk of denial of service on Linux servers running the vulnerable ksmbd SMB server component. This can disrupt file sharing and network services relying on SMB, affecting business continuity and productivity. Critical infrastructure sectors such as finance, healthcare, telecommunications, and government agencies that use Linux-based SMB servers could experience service outages or degraded performance. The vulnerability's network-exploitable nature means attackers can remotely trigger resource exhaustion without credentials, increasing the risk of widespread disruption. Organizations with large-scale Linux deployments or those using SMB for internal or external file sharing are particularly at risk. Although no data breach or integrity compromise is expected, availability impacts can lead to operational delays and increased incident response costs. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits post-disclosure. European entities must consider this vulnerability in their risk assessments and incident response planning.

References

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