VulnerabilityPublished 15 Oct 2025Updated 26 Feb 2026

CVE-2025-61938: F5 BIG-IP · Improper Validation of Specified Quantity in Input

Affects F5 BIG-IPSource CVE Database V5

Not known to be exploited · CVSS 7.5 High.

Data as of 26 Oct 2026, 11:42 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 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 =17.5.0 =17.1.0	Fixed in–

AI-suggested

To mitigate CVE-2025-61938, organizations should: 1) Immediately review and restrict the length of URLs configured in the Data Guard Protection Enforcement setting to not exceed 1024 characters, avoiding manual or automated policy configurations that could trigger the vulnerability. 2) Monitor the stability of the 'bd' process and set up alerts for unexpected terminations or service disruptions in BIG-IP devices. 3) Apply any vendor-released patches or updates as soon as they become available, even if the current versions are still supported. 4) Implement network-level protections such as rate limiting and input validation to reduce the likelihood of maliciously crafted long URLs reaching the BIG-IP device. 5) Consider deploying redundant BIG-IP devices or failover mechanisms to maintain availability in case of process crashes. 6) Engage with F5 support for guidance and potential workarounds until official patches are released. 7) Regularly audit security policies and configurations to ensure compliance with recommended limits and best practices.

Description

When a BIG-IP Advanced WAF or ASM security policy is configured with a URL greater than 1024 characters in length for the Data Guard Protection Enforcement setting, either manually or through the automatic Policy Builder, the bd process can terminate repeatedly. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Impact

The primary impact of CVE-2025-61938 is a denial-of-service condition on F5 BIG-IP devices running affected versions, caused by the repeated termination of the 'bd' process. This can lead to unavailability of critical security functions such as web application firewall protections and application security enforcement, exposing organizations to increased risk from other attacks due to disabled or degraded defenses. Enterprises relying on BIG-IP for traffic management and security may experience service disruptions, potentially affecting business continuity and customer trust. The vulnerability does not expose sensitive data or allow unauthorized access but can indirectly increase risk by disabling protective controls. Given the remote, unauthenticated exploitability and the widespread deployment of BIG-IP in large enterprises, service providers, and government networks, the impact can be significant, especially in environments requiring high availability and robust security.

CWE-1284Improper Validation of Specified Quantity in Input (opens in a new tab)
Base weakness
The product receives input that is expected to specify a quantity (such as size or length), but it does not validate or incorrectly validates that the quantity has the required properties.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

my.f5.com/manage/s/article/K000156624 (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

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

WeaknessesCWE-1284

Technical details

References

Community reviews

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