Bug ID 744536: HTTP/2 may garble large headers

Last Modified: Aug 19, 2026

Affected Product(s):
BIG-IP LTM(all modules)

Known Affected Versions:
11.6.0, 11.6.0 hf1, 11.6.0 hf2, 11.6.0 hf3, 11.6.0 hf4, 11.6.0 hf5, 11.6.0 hf6, 11.6.0 hf7, 11.6.0 hf8, 11.6.1, 11.6.1 hf1, 11.6.1 hf2, 11.6.2, 11.6.2 hf1, 11.6.3, 11.6.3.1, 11.6.3.2, 11.6.3.3, 11.6.3.4, 11.6.4, 11.6.5, 11.6.5.1, 11.6.5.2, 11.6.5.3, 12.0.0, 12.0.0 hf1, 12.0.0 hf2, 12.0.0 hf3, 12.0.0 hf4, 12.1.0, 12.1.0 hf1, 12.1.0 hf2, 12.1.1, 12.1.1 hf1, 12.1.1 hf2, 12.1.2, 12.1.2 hf1, 12.1.2 hf2, 12.1.3, 12.1.3.1, 12.1.3.2, 12.1.3.3, 12.1.3.4, 12.1.3.5, 12.1.3.6, 12.1.3.7, 12.1.4

Fixed In:
12.1.4.1

Opened: Sep 19, 2018

Severity: 3-Major

Symptoms

The HTTP/2 filter may incorrectly encode large headers.

Impact

Application functionality may be disrupted because large header values, such as for cookies, may be truncated when passed to the endpoint.

Conditions

A header that encodes to larger than 2048 bytes.

Workaround

None.

Fix Information

The HTTP/2 filter now correctly encodes large HTTP headers.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips