F5 BIG-IP APM Heap-based Buffer Overflow Vulnerability
Exploited since 2026-09-22. 1 of 8 rule sources name it; Cloudflare blocks by default.
When a BIG-IP APM access policy and an OAuth profile are configured on a virtual server, specific malicious traffic can lead to remote code execution (RCE). This vulnerability is only present when BIG-IP APM is configured as an OAuth… More
When a BIG-IP APM access policy and an OAuth profile are configured on a virtual server, specific malicious traffic can lead to remote code execution (RCE). This vulnerability is only present when BIG-IP APM is configured as an OAuth Authorization Server. Deployments using APM strictly as an OAuth Client / Resource Server (without OAuth authorization server profiles configured) are not affected by this vulnerability. Impact: This vulnerability allows an unauthenticated attacker to perform remote code execution. The BIG-IP system in Appliance mode is also vulnerable. This is a data plane issue; there is no control plane exposure. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
Edge coverage
Claimed by vendorsAsk Vigil
AI · answers from this pageWorkers AI (Llama 3.3). Can be wrong: check the cited source.
Severity, decoded
CVSS 4.0Exploitable over the network, with no privileges and no user interaction, leading to full loss of confidentiality, integrity and availability.
How the score is built
- Attack vectorAn attacker can reach it over the internet; no access to your network needed.Network
- Attack complexityNo built-in defences have to be bypassed; the attack works reliably.Low
- Attack requirementsThe attack works without any special deployment or timing conditions.None
- Privileges requiredNo account or login is needed.None
- User interactionNo one has to click or open anything; the attack works on its own.None
- Confidentiality impact (vulnerable system)An attacker can read all data the affected component holds, or the most sensitive parts of it.High
- Integrity impact (vulnerable system)An attacker can change any data or files the affected component protects.High
- Availability impact (vulnerable system)An attacker can take the component down completely or keep it from serving anyone.High
- Confidentiality impact (other systems)Other systems' data is not exposed.None
- Integrity impact (other systems)Other systems' data cannot be changed.None
- Availability impact (other systems)Other systems keep working normally.None
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NAttackers are exploiting this in the wild.
Attackers can script the attack end to end and hit many targets at once.
A successful attack gives full control over the affected software or all of its data.
Public exploits
None foundNo exploit in Exploit-DB or Metasploit, and no scanner template. That lowers, but doesn't remove, the chance of mass exploitation.
Timeline
- 2026-09-22CVE publishedCVE List
- 2026-09-22Added to CISA KEVConfirmed exploitation in the wild
- 2026-10-06Cloudflare ships a ruleF5 BIG-IP - UnAuth Heap-Overflow - CVE:CVE-2026-94127
Vendor statements
QuotedCloudflareWAF Managed Rules
First rule 2026-10-06, 14 days after the CVE was published.
F5 BIG-IP - UnAuth Heap-Overflow - CVE:CVE-2026-94127. Previous action: Log. New action: Block. This is a new detection.
AWSAWS WAF Managed Rules
We found no public statement from this vendor naming this CVE. That is not proof of no protection: generic rules may still catch it. AWS often describes a vulnerability without naming its CVE (for example "Log4j"). We count only entries that name the CVE, so AWS coverage is understated.
Microsoft AzureFront Door and Application Gateway WAF (DRS)
We found no public statement from this vendor naming this CVE. That is not proof of no protection: generic rules may still catch it. The rule tables name CVEs but carry no dates, so Azure is left out of every time-to-rule figure.
Google CloudCloud Armor preconfigured WAF rules
We found no public statement from this vendor naming this CVE. That is not proof of no protection: generic rules may still catch it. Google names few CVEs: the release notes start in May 2024 and the rules reference lists CVEs without dates. Its cve-canary rules are opt-in.
FastlyNext-Gen WAF virtual patches
The CVE predates the oldest entry in this vendor's public feed, so a rule may exist that we cannot see.
F5Attack signatures (Distributed Cloud WAF)
We found no public statement from this vendor naming this CVE. That is not proof of no protection: generic rules may still catch it. Each signature lists the CVEs it references, with its id and date. F5 does not state a default action; signatures enforce once staging ends in your policy.
AkamaiApp & API Protector (Adaptive Security Engine)
This vendor publishes no machine-readable rule changelog we can check.
OWASP CRSCore Rule Set (open source, used inside many WAFs)
We found no public statement from this vendor naming this CVE. That is not proof of no protection: generic rules may still catch it. CRS rarely names CVEs: it relies on generic detections. Our own lab measures what it actually blocks.
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