BIG-IP: Incorrect Calculation of Buffer Size
CVE-2024-23805 is a high-severity incorrect calculation of buffer size vulnerability in BIG-IP from F5, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 17.1.1, 16.1.4, 15.1.10 as the first without the flaw, so updating BIG-IP to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.52% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update BIG-IP to 17.1.1 or 16.1.4 or 15.1.10, whichever matches your release line, or a later version.
- Update Big-ip Advanced Web Application Firewall to 15.1.10 or 16.1.4, whichever matches your release line, or a later version.
- Update Big-ip Application Security Manager to 15.1.10 or 16.1.4, whichever matches your release line, or a later version.
- Read the advisory on my.f5.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| F5 | BIG-IP | 17.1.0 up to, but not including, 17.1.1; 16.1.0 up to, but not including, 16.1.4; 15.1.0 up to, but not including, 15.1.10 | 17.1.1, 16.1.4, 15.1.10 |
| F5 | Big-ip Advanced Web Application Firewall | 15.1.0 up to, but not including, 15.1.10; 16.1.0 up to, but not including, 16.1.4; 17.1.0 | 15.1.10, 16.1.4 |
| F5 | Big-ip Application Security Manager | 15.1.0 up to, but not including, 15.1.10; 16.1.0 up to, but not including, 16.1.4; 17.1.0 | 15.1.10, 16.1.4 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | CNA (f5.com) |
| CVSS 3.1 | 7.5 | High | NVD |
Official description
Undisclosed requests can cause the Traffic Management Microkernel (TMM) to terminate. For the Application Visibility and Reporting module, this may occur when the HTTP Analytics profile with URLs enabled under Collected Entities is configured on a virtual server and the DB variables avr.IncludeServerInURI or avr.CollectOnlyHostnameFromURI are enabled. For BIG-IP Advanced WAF and ASM, this may occur when either a DoS or Bot Defense profile is configured on a virtual server and the DB variables avr.IncludeServerInURI or avr.CollectOnlyHostnameFromURI are enabled. Note: The DB variables avr.IncludeServerInURI and avr.CollectOnlyHostnameFromURI are not enabled by default. For more information about the HTTP Analytics profile and the Collect URLs setting, refer to K30875743: Create a new Analytics profile and attach it to your virtual servers https://my.f5.com/manage/s/article/K30875743 . Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incorrect Calculation of Buffer Size
The product does not correctly calculate the size to be used when allocating a buffer.
How developers prevent this class of flaw
- When allocating a buffer for the purpose of transforming, converting, or encoding an input, allocate enough memory to handle the largest possible encoding. For example, in a routine that converts & characters to & for HTML entity encoding, the output buffer needs to be at least 5 times as large as the input buffer.
- Understand the programming language's underlying representation and how it interacts with numeric calculation (CWE-681). Pay close attention to byte size discrepancies, precision, signed/unsigned distinctions, truncation, conversion and casting between types, not-a-number calculations, and how the language handles numbers that are too large or too small for its underlying representation. Also be careful to account for 32-bit, 64-bit, and other potential differences that may affect the numeric representation.
- Perform input validation on any numeric input by ensuring that it is within the expected range. Enforce that the input meets both the minimum and maximum requirements for the expected range.
More Incorrect Calculation of Buffer Size vulnerabilities (CWE-131)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in BIG-IP
- 9.8 Critical severity
F5 BIG-IP APM Heap-based Buffer Overflow Exploited
- 8.8 High severity
- 7.5 High severity
- 8.7 High severity
- 8.7 High severity
- 7.5 High severity
Recent Incorrect Calculation of Buffer Size vulnerabilities
- 7.5 High severity
- 9.8 Critical severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
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