Bug ID 1787457: GRPC communication may fail when server responds without trailers and any payload

Last Modified: Sep 26, 2026

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

Known Affected Versions:
17.1.1, 17.1.1.1, 17.1.1.2, 17.1.1.3, 17.1.1.4, 17.1.2, 17.1.2.1, 17.1.2.2, 17.1.3, 17.1.3.1, 17.1.3.2, 17.1.3.4, 17.1.3.5

Fixed In:
21.1.0

Opened: Jan 20, 2025

Severity: 4-Minor

Symptoms

Virtual server has http2 profile and handles GRPC traffic. When the HTTP Trailer with GRPC code is omitted, i.e. servers sends a response with no payload, BIG-IP issues HEADERS frame followed by empty DATA frame with END_STREAM flag, breaking GRPC communication.

Impact

GRPC client sends RST_STREAM, breaking GRPC communication with the server.

Conditions

GRPC server send a response without Trailers and any payload, lacking any sizing for the payload in HTTP headers.

Workaround

None

Fix Information

BIG-IP recognizes HTTP/2 responses without any payload and forwards it to the client in HEADERS frame with END_STREAM flag.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips