VulnerabilityPublished 25 Apr 2023Updated 21 Oct 2025

CVE-2023-29552: IETF Service Location Protocol (SLP)

Affects IETF Service Location Protocol (SLP)Source CVE Database V5

Exploited in the wild · KEV due 29 Nov 2023 · 63% EPSS : apply the vendor's fix or mitigations to IETF Service Location Protocol (SLP) now.

Data as of 26 Oct 2026, 08:30 UTC

CVSS 3.1 base score

7.5High

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

KEV deadline: 29 Nov 2023 US federal agencies must patch by this date; a sensible deadline for everyone else.
EPSS: 63.9% chance of exploitation in 30 days – higher than 99% 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:H

Attack Vector: Network
Attack Complexity: Low
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: 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: 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

t = 0 is the CVE’s publication on cve.org

Disclosed: evidence found.
CVE published 25 Apr 2023
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: evidence found.
Listed in CISA KEV 197 days after disclosure
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

CVE ID reserved
by MITRE Corporation
7 Apr 2023, 18 days before disclosure
CVE published
on cve.org
25 Apr 2023, t = 0
Added to CISA KEV (opens in a new tab)
exploitation confirmed
8 Nov 2023, 197 days after disclosure
KEV remediation due
US federal deadline
29 Nov 2023, 218 days after disclosure

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA KEV (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

Apply mitigations per vendor instructions or disable SLP service or port 427/UDP on all systems running on untrusted networks, including those directly connected to the Internet.

Description

The Service Location Protocol (SLP, RFC 2608) allows an unauthenticated, remote attacker to register arbitrary services. This could allow the attacker to use spoofed UDP traffic to conduct a denial-of-service attack with a significant amplification factor.

Impact

For European organizations, the primary impact is on network availability and service continuity. Enterprises and service providers using SLP for service discovery in their internal networks or across data centers may experience amplified denial-of-service attacks that can disrupt critical business operations. This can affect sectors such as telecommunications, finance, healthcare, and government services where network reliability is paramount. Amplification attacks leveraging this vulnerability could also be used as part of broader DDoS campaigns targeting European infrastructure, potentially causing collateral damage to unrelated services sharing network resources. The lack of authentication means attackers can exploit this vulnerability remotely without prior access, increasing the attack surface. Additionally, organizations with legacy systems or insufficient network segmentation are at higher risk. The disruption caused by such attacks could lead to financial losses, reputational damage, and regulatory compliance issues under frameworks like GDPR if service outages impact customer data processing.

Mitigation

To mitigate CVE-2023-29552, organizations should implement the following specific measures: 1) Disable SLP on all devices and servers where it is not explicitly required to reduce the attack surface. 2) For systems that require SLP, restrict UDP port 427 traffic to trusted internal networks using firewall rules and access control lists to prevent external spoofed packets. 3) Employ network ingress filtering (BCP 38) to prevent IP address spoofing within the organization's network, reducing the risk of amplification attacks. 4) Monitor network traffic for unusual spikes in UDP packets on port 427 indicative of exploitation attempts. 5) Engage with vendors and apply patches or firmware updates as they become available to address this vulnerability in specific implementations. 6) Consider deploying rate limiting on UDP traffic to limit the potential amplification effect. 7) Conduct regular security assessments and penetration tests focusing on network protocols like SLP to identify and remediate similar weaknesses. 8) Educate network administrators about the risks of unauthenticated service registration protocols and best practices for secure network design.

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AI analysisMachine-generated, updated 28 Oct 2025, 23:03 UTC

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