CVE-2025-54809VulnerabilityPublished 13 Aug 2025

CVE-2025-54809: F5 Access · Improper Certificate Validation

Affects F5 AccessSource CVE Database V5

Not known to be exploited · CVSS 7.4 High.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

7.4High

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 16% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Attack Vector: Network
Attack Complexity: High
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: None

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: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
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: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 13 Aug 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 F5 Access	Affected =3.1.0	Fixed in–

AI-suggested

European organizations should prioritize upgrading all F5 Access for Android clients to version 3.1.2 or later, where the certificate validation issue is resolved. Network administrators should enforce strict mobile device management (MDM) policies to ensure compliance with updated software versions. Additionally, organizations can implement network-level protections such as TLS interception detection tools and anomaly-based intrusion detection systems to identify suspicious MitM attempts. Employing certificate pinning or additional endpoint certificate validation mechanisms can further reduce risk. Regular security awareness training should emphasize the risks of connecting to untrusted networks, as attackers may exploit this vulnerability primarily in hostile or public Wi-Fi environments. Monitoring VPN logs for unusual connection patterns or certificate anomalies can help detect exploitation attempts early. Finally, organizations should maintain an inventory of all devices using F5 Access to ensure no outdated clients remain in use.

Description

F5 Access for Android before version 3.1.2 which uses HTTPS does not verify the remote endpoint identity. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Impact

For European organizations, this vulnerability poses significant risks, especially for enterprises relying on F5 Access for secure remote connectivity. The improper certificate validation could allow attackers to intercept sensitive corporate data, including credentials, confidential communications, and proprietary information. This is particularly critical for sectors with stringent data protection requirements such as finance, healthcare, and government institutions under GDPR regulations. The exposure could lead to data breaches, regulatory penalties, and erosion of trust. Additionally, compromised VPN sessions could serve as a foothold for further lateral movement within corporate networks, escalating the impact. Given the high reliance on mobile devices for remote work in Europe, especially Android devices, the threat surface is considerable. The absence of known exploits in the wild suggests proactive patching can prevent exploitation, but the window of vulnerability remains until affected versions are updated. The high attack complexity somewhat limits mass exploitation but does not eliminate targeted attacks by skilled adversaries.

Summary

CVE-2025-54809 is a high-severity vulnerability identified in F5 Access for Android versions prior to 3.1.2. The vulnerability stems from improper certificate validation (CWE-295) during HTTPS connections, where the application fails to verify the remote endpoint's identity. This flaw means that when the F5 Access client establishes an HTTPS connection, it does not properly validate the server's TLS certificate, allowing an attacker to perform man-in-the-middle (MitM) attacks by presenting a fraudulent certificate. Consequently, an attacker positioned on the network path could intercept, modify, or redirect sensitive communications without detection. The vulnerability affects version 3.1.0 specifically, with no indication of exploitation in the wild to date. The CVSS v3.1 base score is 7.4, reflecting a high severity due to the potential for complete compromise of confidentiality and integrity of data transmitted via the VPN or secure tunnel established by F5 Access. The attack vector is network-based (AV:N), requires no privileges (PR:N), no user interaction (UI:N), but has a high attack complexity (AC:H), indicating that while exploitation is possible remotely, it may require specific conditions or capabilities. The vulnerability does not impact availability. Since F5 Access is a widely used VPN client for secure remote access, this flaw undermines the fundamental trust model of TLS connections, potentially exposing enterprise network traffic to interception and manipulation.

CWE-295Improper Certificate Validation (opens in a new tab)
Base weaknessOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
The product does not validate, or incorrectly validates, a certificate.
Architecture and Design · Implementation
Certificates should be carefully managed and checked to assure that data are encrypted with the intended owner's public key.
Implementation
If certificate pinning is being used, ensure that all relevant properties of the certificate are fully validated before the certificate is pinned, including the hostname.
OWASP Cheat Sheets
Transport Layer Protection (opens in a new tab)
TLS Cipher String (opens in a new tab)
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V9.2.1 (opens in a new tab)
V1.9.2 (opens in a new tab)
V2.8.5 (opens in a new tab)
Attack patterns
Creating a Rogue Certification Authority Certificate (opens in a new tab)
Signature Spoofing by Improper Validation (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

my.f5.com/manage/s/article/K000152049 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 13 Aug 2025, 15:18 UTC

WeaknessesCWE-295

Technical details

References

Community reviews

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