VulnerabilityPublished 15 Oct 2025Updated 26 Feb 2026

CVE-2025-59781: F5 BIG-IP · Incomplete Cleanup

Affects F5 BIG-IPSource CVE Database V5

Not known to be exploited · CVSS 7.5 High.

Data as of 26 Oct 2026, 14:05 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 =17.1.0 =16.1.0 =15.1.0	Fixed in–

AI-suggested

Organizations should immediately assess whether their F5 BIG-IP deployments are running affected versions (15.1.0, 16.1.0, or 17.1.0) with DNS cache enabled on virtual servers. If so, they should prioritize upgrading to a fixed version once available from F5 or apply any interim mitigations recommended by the vendor. In the absence of patches, administrators can consider disabling DNS caching on virtual servers if operationally feasible to prevent memory buildup. Monitoring memory utilization and DNS cache size on BIG-IP devices can help detect abnormal resource consumption early. Network-level controls such as rate limiting or filtering of DNS queries to BIG-IP virtual servers may reduce exposure to exploit attempts. Regularly reviewing device configurations and applying security best practices for BIG-IP management will also reduce risk. Finally, maintaining up-to-date inventory and patch management processes for critical infrastructure devices is essential to respond promptly to such vulnerabilities.

Description

When DNS cache is configured on a BIG-IP or BIG-IP Next CNF virtual server, undisclosed DNS queries 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-2025-59781 is on the availability of F5 BIG-IP devices configured with DNS caching. By exploiting incomplete cleanup of DNS cache entries, an attacker can cause memory resource exhaustion, potentially leading to system slowdowns, crashes, or denial of service. This can disrupt critical network functions such as load balancing, application delivery, and security services that rely on BIG-IP devices. Organizations worldwide that depend on BIG-IP for managing traffic and securing applications may experience outages or degraded performance, affecting business continuity and user experience. The vulnerability does not compromise data confidentiality or integrity but can indirectly impact operational stability. Given the widespread deployment of F5 BIG-IP in enterprise, government, and service provider networks, the threat could have broad implications, especially in environments with high DNS query volumes or where DNS caching is heavily utilized. The ease of remote exploitation without authentication increases the risk of automated attacks targeting vulnerable devices.

CWE-459Incomplete Cleanup (opens in a new tab)
Base weakness
The product does not properly "clean up" and remove temporary or supporting resources after they have been used.
Architecture and Design · Implementation
Temporary files and other supporting resources should be deleted/released immediately after they are no longer needed.
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

my.f5.com/manage/s/article/K000150637 (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, 05:47 UTC

WeaknessesCWE-459

Technical details

References

Community reviews

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