CVE-2025-61935VulnerabilityPublished 15 Oct 2025Updated 26 Feb 2026

CVE-2025-61935: F5 BIG-IP · Unchecked Return Value

Affects F5 BIG-IPSource CVE Database V5

Not known to be exploited · CVSS 7.5 High.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

7.5High

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 28% 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 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

Affected software

Product	Affected	Fixed in
F5 BIG-IP	Affected =17.5.0 =17.1.0 =15.1.0	Fixed in–

AI-suggested

1. Apply official patches or updates from F5 as soon as they become available for affected BIG-IP versions (15.1.0, 17.1.0, 17.5.0). 2. In the absence of patches, consider temporarily disabling Advanced WAF or ASM policies on virtual servers if feasible, to mitigate triggering the bd process failure. 3. Implement network-level protections such as rate limiting, web application firewalls, and intrusion prevention systems to detect and block suspicious or malformed requests targeting the BIG-IP devices. 4. Monitor BIG-IP system logs and process health metrics closely to detect early signs of bd process termination or instability. 5. Restrict access to management and virtual server interfaces to trusted networks and enforce strict access controls to reduce exposure. 6. Employ anomaly detection tools to identify unusual traffic patterns that could indicate exploitation attempts. 7. Maintain an incident response plan specifically addressing potential denial of service scenarios affecting BIG-IP infrastructure. 8. Engage with F5 support and subscribe to security advisories for timely updates and guidance. 9. Consider network segmentation to isolate critical BIG-IP devices and limit the blast radius of potential attacks. 10. Conduct regular security assessments and penetration testing to validate the effectiveness of mitigations and identify residual risks.

Description

When a BIG IP Advanced WAF or ASM security policy is configured on a virtual server, undisclosed requests can cause the bd process to terminate. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Impact

The primary impact of CVE-2025-61935 is a denial of service condition on F5 BIG-IP devices configured with Advanced WAF or ASM policies. This can lead to service outages affecting load balancing, application delivery, and security enforcement functions critical to enterprise and service provider networks. Disruption of BIG-IP services can cause downtime for hosted applications, degrade user experience, and potentially interrupt business operations. Given the widespread use of F5 BIG-IP in large enterprises, cloud providers, and telecommunications infrastructure, the impact can be significant, especially for organizations relying on these devices for secure and reliable application delivery. The vulnerability does not compromise data confidentiality or integrity, but the loss of availability can have cascading effects on dependent systems and services. Attackers can exploit this vulnerability remotely without authentication, increasing the risk of widespread automated attacks or targeted disruption campaigns. Organizations with high availability requirements and those in sectors such as finance, healthcare, government, and critical infrastructure are particularly vulnerable to the operational impact of this DoS vulnerability.

CWE-252Unchecked Return Value (opens in a new tab)
Base weaknessLikelihood of exploit: LowOWASP Top 10 A10:2025: Mishandling of Exceptional Conditions (opens in a new tab)
The product does not check the return value from a method or function, which can prevent it from detecting unexpected states and conditions.
Implementation
Check the results of all functions that return a value and verify that the value is expected.
Implementation
For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished.
Implementation
Ensure that you account for all possible return values from the function.
OWASP Cheat Sheets
Logging (opens in a new tab)
Error Handling (opens in a new tab)
OWASP ASVS 4.0.3
V11.1.7 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

my.f5.com/manage/s/article/K000154664 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 27 Feb 2026, 06:04 UTC

WeaknessesCWE-252

Technical details

References

Community reviews

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