CyberSecBulletin
CVE-2025-36557NVD status: Analyzed

BIG-IP: Buffer Copy without Checking Size of Input

Published Updated By the CyberSecBulletin desk

CVE-2025-36557 is a high-severity buffer copy without checking size of input 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 17.1.2, 16.1.5 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 0.44% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update BIG-IP to 17.1.2 or 16.1.5, whichever matches your release line, or a later version.
  2. Update BIG-IP Next SPK to 2.0.0 or 1.7.9, whichever matches your release line, or a later version.
  3. Update BIG-IP Next CNF to 1.4.0 or a later version.
  4. Read the advisory on my.f5.com for workarounds and exact fixed builds.
  5. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
F5BIG-IP17.1.0 up to, but not including, 17.1.2; 16.1.0 up to, but not including, 16.1.517.1.2, 16.1.5
F5BIG-IP Next SPK1.8.0 up to, but not including, 2.0.0; 1.7.0 up to, but not including, 1.7.92.0.0, 1.7.9
F5BIG-IP Next CNF1.1.0 up to, but not including, 1.4.01.4.0
F5Big-ip Access Policy Manager16.1.0 up to, but not including, 16.1.5; 17.1.0 up to, but not including, 17.1.216.1.5, 17.1.2
F5Big-ip Advanced Firewall Manager16.1.0 up to, but not including, 16.1.5; 17.1.0 up to, but not including, 17.1.216.1.5, 17.1.2
F5Big-ip Analytics16.1.0 up to, but not including, 16.1.5; 17.1.0 up to, but not including, 17.1.216.1.5, 17.1.2
F5Big-ip Application Acceleration Manager16.1.0 up to, but not including, 16.1.5; 17.1.0 up to, but not including, 17.1.216.1.5, 17.1.2
F5Big-ip Application Security Manager16.1.0 up to, but not including, 16.1.5; 17.1.0 up to, but not including, 17.1.216.1.5, 17.1.2
F5Big-ip Domain Name System16.1.0 up to, but not including, 16.1.5; 17.1.0 up to, but not including, 17.1.216.1.5, 17.1.2
F5Big-ip Fraud Protection Service16.1.0 up to, but not including, 16.1.5; 17.1.0 up to, but not including, 17.1.216.1.5, 17.1.2
F5Big-ip Global Traffic Manager16.1.0 up to, but not including, 16.1.5; 17.1.0 up to, but not including, 17.1.216.1.5, 17.1.2
F5Big-ip Link Controller16.1.0 up to, but not including, 16.1.5; 17.1.0 up to, but not including, 17.1.216.1.5, 17.1.2
F5Big-ip Local Traffic Manager16.1.0 up to, but not including, 16.1.5; 17.1.0 up to, but not including, 17.1.216.1.5, 17.1.2
F5Big-ip Policy Enforcement Manager16.1.0 up to, but not including, 16.1.5; 17.1.0 up to, but not including, 17.1.216.1.5, 17.1.2
F5Big-ip Next Cloud-native Network Functions1.1.0 up to, but not including, 1.4.01.4.0
F5Big-ip Next Service Proxy For Kubernetes1.7.0 up to, but not including, 1.7.9; 1.8.0 through 1.9.21.7.9

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 CNA (f5.com).

Scoring systemScoreSeverityScored by
CVSS 4.08.7HighCNA (f5.com)
CVSS 3.17.5HighCNA (f5.com)

Official description

When an HTTP profile with the Enforce RFC Compliance option is configured on a virtual server, undisclosed requests can cause the Traffic Management Microkernel (TMM) to terminate. 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: Buffer Copy without Checking Size of Input

The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.

How developers prevent this class of flaw

  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples include the Safe C String Library (SafeStr) by Messier and Viega, and the Strsafe.h library from Microsoft. These libraries provide safer versions of overflow-prone string-handling functions.
  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.

More Buffer Copy without Checking Size of Input vulnerabilities (CWE-120)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in BIG-IP

All BIG-IP vulnerabilities

Recent Buffer Copy without Checking Size of Input vulnerabilities

Spotted an error? Tell us.