CVE-2025-53538VulnerabilityPublished 22 Jul 2025

CVE-2025-53538: OISF suricata · Unthrottled Resource Allocation

Affects OISF suricataSource CVE Database V5

Not known to be exploited · CVSS 7.5 High : upgrade to 7.0.11 soon.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

7.5High

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

EPSS: 0.5% chance of exploitation in 30 days – higher than 44% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 7.0.11

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

Disclosed: evidence found.
CVE published 22 Jul 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 2026-10-25.

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

Upgrade oisf/suricata to 7.0.11.

Affected software

Product	Affected	Fixed in
GitHuboisf/suricata`pkg:github/oisf/suricata`Other threats	Affected <7.0.11	Fixed in 7.0.11

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

European organizations should prioritize upgrading Suricata to version 7.0.11 or 8.0.0 (or later) as soon as possible to fully remediate the vulnerability. Until upgrades can be applied, organizations should disable the HTTP/2 parser in Suricata configurations to prevent processing of vulnerable HTTP/2 frames. Deploying the recommended Suricata signature that drops HTTP/2 frames on stream 0 can serve as an effective temporary workaround to limit memory exhaustion. Network administrators should monitor Suricata instances for unusual memory usage or crashes that could indicate exploitation attempts. Additionally, organizations should implement network segmentation and limit exposure of Suricata sensors to untrusted networks to reduce attack surface. Regularly reviewing and updating IDS/IPS signatures and configurations to detect anomalous HTTP/2 traffic patterns can also help mitigate risks. Finally, maintaining robust incident response plans to quickly address potential denial of service events will minimize operational impact.

Description

Suricata is a network IDS, IPS and NSM engine developed by the OISF (Open Information Security Foundation) and the Suricata community. In versions 7.0.10 and below and 8.0.0-beta1 through 8.0.0-rc1, mishandling of data on HTTP2 stream 0 can lead to uncontrolled memory usage, leading to loss of visibility. Workarounds include disabling the HTTP/2 parser, and using a signature like drop http2 any any -> any any (frame:http2.hdr; byte_test:1,=,0,3; byte_test:4,=,0,5; sid: 1;) where the first byte test tests the HTTP2 frame type DATA and the second tests the stream id 0. This is fixed in versions 7.0.11 and 8.0.0.

Impact

For European organizations, the impact of this vulnerability is significant, especially for those relying on Suricata for network security monitoring and intrusion detection. The uncontrolled memory usage can lead to denial of service, causing Suricata to crash or become unresponsive, which results in loss of visibility into network traffic and potential blind spots for detecting malicious activity. This can delay incident detection and response, increasing the risk of successful cyberattacks or data breaches. Critical infrastructure sectors such as finance, energy, telecommunications, and government agencies that deploy Suricata as part of their security stack are particularly at risk. The disruption of IDS/IPS capabilities can also affect compliance with European data protection regulations like GDPR, which require adequate security measures to protect personal data. Additionally, the vulnerability could be exploited remotely without authentication, increasing the risk of widespread attacks if threat actors target exposed Suricata deployments.

Summary

CVE-2025-53538 is a high-severity vulnerability affecting Suricata, an open-source network intrusion detection and prevention system (IDS/IPS) and network security monitoring (NSM) engine developed by the Open Information Security Foundation (OISF). The vulnerability arises from improper handling of data on HTTP/2 stream 0 in Suricata versions 7.0.10 and below, as well as versions 8.0.0-beta1 through 8.0.0-rc1. Specifically, Suricata fails to impose limits or throttling on resource allocation when processing HTTP/2 stream 0 frames, leading to uncontrolled memory consumption. This flaw is categorized under CWE-770 (Allocation of Resources Without Limits or Throttling) and CWE-400 (Uncontrolled Resource Consumption). The exploitation of this vulnerability does not impact confidentiality or integrity but results in a denial of service condition by exhausting memory resources, causing Suricata to lose visibility into network traffic. This can critically impair network security monitoring and intrusion detection capabilities. The vulnerability can be mitigated temporarily by disabling the HTTP/2 parser or by deploying a custom Suricata signature that drops HTTP/2 frames on stream 0, effectively preventing the problematic frames from being processed. The issue is resolved in Suricata versions 7.0.11 and 8.0.0 and later. The CVSS v3.1 base score is 7.5, reflecting a high severity due to network attack vector, no required privileges or user interaction, and a significant impact on availability.

CWE-770Allocation of Resources Without Limits or Throttling (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #25
The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
Requirements
Clearly specify the minimum and maximum expectations for capabilities, and dictate which behaviors are acceptable when resource allocation reaches limits.
Architecture and Design
Limit the amount of resources that are accessible to unprivileged users. Set per-user limits for resources. Allow the system administrator to define these limits. Be careful to avoid CWE-410.
Architecture and Design
Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
OWASP ASVS 4.0.3
V8.1.4 (opens in a new tab)
V13.4.1 (opens in a new tab)
V11.1.4 (opens in a new tab)
Attack patterns
XML Ping of the Death (opens in a new tab)
Exponential Data Expansion (opens in a new tab)
Serialized Data Parameter Blowup (opens in a new tab)
Serialized Data with Nested Payloads (opens in a new tab)
Oversized Serialized Data Payloads (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-400Uncontrolled Resource Consumption (opens in a new tab)
Class weaknessLikelihood of exploit: High
The product does not properly control the allocation and maintenance of a limited resource.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design
Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place.
Architecture and Design
Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or; uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed.
Architecture and Design
Ensure that protocols have specific limits of scale placed on them.
OWASP Cheat Sheets
File Upload (opens in a new tab)
OWASP ASVS 4.0.3
V12.1.1 (opens in a new tab)
Attack patterns
XML Ping of the Death (opens in a new tab)
Regular Expression Exponential Blowup (opens in a new tab)
Sustained Client Engagement (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 30 Jul 2025, 01:32 UTC

WeaknessesCWE-770, CWE-400

Technical details

References

Community reviews

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