CVE-2025-61581VulnerabilityPublished 16 Oct 2025Updated 4 Nov 2025

CVE-2025-61581: Apache Traffic Control · ReDoS

Affects Apache Traffic ControlSource CVE Database V5

Not known to be exploited · CVSS 7.5 High · end of life, no fix coming : replace or isolate Apache Traffic Control; no fix will be released.

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.

EPSS: 0.7% chance of exploitation in 30 days – higher than 54% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: None coming – the product is end of life

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 16 Oct 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 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

No fix will be released: Apache Traffic Control is end of life. Replace it, or isolate it from untrusted networks until you can.

Affected software

Product	Affected	Fixed in
Apache Software Foundation Apache Traffic Control	Affected =0	Fixed in–

AI-suggested

Due to the retirement of Apache Traffic Control and absence of patches for CVE-2025-61581, mitigation must focus on compensating controls and migration strategies. First, restrict access to the Traffic Router management interface strictly to trusted internal users and networks using network segmentation, firewall rules, and VPNs to prevent unauthorized access. Implement strong authentication and monitoring on the management interface to detect and respond to suspicious activity. Evaluate the feasibility of disabling or limiting the use of regular expression pattern inputs if configurable. Plan and execute migration away from Apache Traffic Control to supported, actively maintained traffic routing solutions that do not exhibit this vulnerability. During transition, consider deploying rate limiting and resource usage monitoring to detect potential abuse of the vulnerable component. Maintain up-to-date network and host-based intrusion detection systems to identify anomalous traffic patterns indicative of exploitation attempts. Document and communicate the risk to relevant stakeholders to ensure awareness and prioritization of remediation efforts.

Description

** UNSUPPORTED WHEN ASSIGNED ** Inefficient Regular Expression Complexity vulnerability in Apache Traffic Control. This issue affects Apache Traffic Control: all versions. People with access to the management interface of the Traffic Router component could specify malicious patterns and cause unavailability. As this project is retired, we do not plan to release a version that fixes this issue. Users are recommended to find an alternative or restrict access to the instance to trusted users. NOTE: This vulnerability only affects products that are no longer supported by the maintainer.

Impact

For European organizations, the primary impact of CVE-2025-61581 is the potential for denial-of-service attacks against Apache Traffic Control deployments, which could disrupt content delivery and traffic routing services. This could lead to service outages affecting web applications, content delivery networks (CDNs), and other dependent services, resulting in operational downtime and potential financial losses. Since the vulnerability does not affect confidentiality or integrity, data breaches are unlikely; however, availability disruptions can degrade user experience and damage organizational reputation. The risk is heightened in environments where the management interface is accessible beyond trusted networks or where Apache Traffic Control is used in critical infrastructure. Given that Apache Traffic Control is retired, organizations cannot rely on vendor patches, increasing the urgency to mitigate or replace the affected software. European sectors such as telecommunications, media, and large enterprises using Apache Traffic Control for traffic routing are particularly vulnerable. The lack of known exploits currently reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits over time.

Summary

CVE-2025-61581 is a vulnerability classified under CWE-1333, which pertains to inefficient regular expression complexity within the Apache Traffic Control project, specifically its Traffic Router component. This flaw allows an attacker who has access to the management interface to submit malicious regular expression patterns that cause excessive computational overhead during pattern matching. This results in a denial-of-service (DoS) condition by exhausting system resources, leading to unavailability of the Traffic Router service. The vulnerability affects all versions of Apache Traffic Control, a project that has been officially retired by the Apache Software Foundation, meaning no patches or updates will be released to address this issue. The CVSS v3.1 score is 7.5 (high severity), reflecting that the attack vector is network-based (AV:N), requires no privileges (PR:N), no user interaction (UI:N), and impacts availability only (A:H) without affecting confidentiality or integrity. Since the management interface is the attack surface, exploitation requires network access to this interface, which is typically restricted but may be exposed in some deployments. No known exploits have been reported in the wild, but the lack of vendor support and patching increases risk over time. The vulnerability highlights the risk of relying on retired software with known issues and the importance of access control to management interfaces in network infrastructure components.

CWE-1333Inefficient Regular Expression Complexity (opens in a new tab)
Base weaknessLikelihood of exploit: High
The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.
Architecture and Design
Use regular expressions that do not support backtracking, e.g. by removing nested quantifiers.
System Configuration
Set backtracking limits in the configuration of the regular expression implementation, such as PHP's pcre.backtrack_limit. Also consider limits on execution time for the process.
Implementation
Do not use regular expressions with untrusted input. If regular expressions must be used, avoid using backtracking in the expression.
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
Regular Expression Exponential Blowup (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Nov 2025, 22:14 UTC

WeaknessesCWE-1333

Technical details

References

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