VulnerabilityPublished 15 Oct 2025Updated 26 Feb 2026

CVE-2025-61974: F5 BIG-IP · Memory Leak

Affects F5 BIG-IPSource CVE Database V5

Not known to be exploited · CVSS 7.5 High.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 3.1 base score

7.5High

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

EPSS: 0.4% chance of exploitation in 30 days – higher than 39% 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

Disclosed: evidence found.
CVE published 15 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 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

Affected software

Product	Affected	Fixed in
F5 BIG-IP	Affected 15.1.0 – 17.5.0 4 affected builds	Fixed in–

AI-suggested

To mitigate CVE-2025-61974, organizations should first verify if their BIG-IP devices are running affected versions (15.1.0, 16.1.0, 17.1.0, or 17.5.0) with client SSL profiles configured on virtual servers. Immediate steps include: 1) Monitoring memory usage closely on BIG-IP devices to detect abnormal increases that could indicate exploitation attempts. 2) Implementing network-level protections such as rate limiting and filtering to restrict potentially malicious traffic patterns targeting SSL profiles. 3) Segregating management and data plane traffic to reduce exposure. 4) Applying any vendor-released patches or hotfixes as soon as they become available. 5) Engaging with F5 support for guidance and potential workarounds, such as disabling or modifying client SSL profiles if feasible without impacting business operations. 6) Conducting regular vulnerability assessments and penetration testing focused on BIG-IP configurations. 7) Ensuring robust incident response plans are in place to quickly address potential denial-of-service incidents. Avoid running unsupported or end-of-support versions to maintain access to security updates.

Description

When a client SSL profile is configured on a virtual server, undisclosed requests can cause an increase in memory resource utilization. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Impact

The primary impact of CVE-2025-61974 is on the availability of F5 BIG-IP devices, which are critical components in many enterprise and service provider networks for managing application traffic and SSL termination. Exploitation can lead to memory exhaustion, causing degraded performance, service slowdowns, or complete denial of service. This can disrupt access to business-critical applications, impacting operational continuity and potentially causing financial and reputational damage. Since the vulnerability can be exploited remotely without authentication, attackers can launch denial-of-service attacks at scale, targeting organizations that rely heavily on BIG-IP for secure and reliable application delivery. The lack of impact on confidentiality and integrity means data breaches or unauthorized data modification are not direct concerns, but service outages can indirectly affect business operations and customer trust. Organizations with high availability requirements and those in sectors such as finance, healthcare, telecommunications, and government are particularly at risk due to the critical nature of their services.

CWE-401Missing Release of Memory after Effective Lifetime (opens in a new tab)
Variant weaknessLikelihood of exploit: Medium
The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.
Implementation · Libraries or Frameworks
Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
Architecture and Design
Use an abstraction library to abstract away risky APIs. Not a complete solution.
Architecture and Design · Build and Compilation
Consider using the Boehm-Demers-Weiser garbage collector (bdwgc), which can help avoid leaks.
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

my.f5.com/manage/s/article/K000156733 (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 27 Feb 2026, 06:06 UTC

WeaknessesCWE-401

Technical details

References

Community reviews

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