CVE-2026-78663

Publication date 8 October 2026

Last updated 6 November 2026

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

9.1 · Critical

Score breakdown

Description

The HTTP/2 server can refund connection-level flow control twice for the same data: Once when a client resets a stream (refunding data for any sent-but-unread portion of the stream), and again when a request handler reads the buffered data. A malicious client can exploit this to bypass the configured connection-level flow control limit (MaxReceiveBufferPerConnection). Total buffered data is still limited by the concurrent stream limit and stream-level flow control.

Read the notes from the security team

Status

Package Ubuntu Release Status
golang-golang-x-net 26.10 stonking
Needs evaluation
26.04 LTS resolute
Needs evaluation
24.04 LTS noble
Needs evaluation
22.04 LTS jammy
Needs evaluation
google-guest-agent 26.10 stonking
Needs evaluation
26.04 LTS resolute
Needs evaluation
24.04 LTS noble
Needs evaluation
22.04 LTS jammy
Needs evaluation
20.04 LTS focal
Needs evaluation
18.04 LTS bionic
Needs evaluation
16.04 LTS xenial
Needs evaluation
google-osconfig-agent 26.10 stonking
Vulnerable
26.04 LTS resolute
Vulnerable
24.04 LTS noble
Vulnerable
22.04 LTS jammy
Vulnerable
20.04 LTS focal
Vulnerable
18.04 LTS bionic
Vulnerable
16.04 LTS xenial
Vulnerable
containerd 26.10 stonking
Needs evaluation
26.04 LTS resolute
Needs evaluation
24.04 LTS noble
Needs evaluation
22.04 LTS jammy
Needs evaluation
20.04 LTS focal
Needs evaluation
18.04 LTS bionic
Needs evaluation
16.04 LTS xenial
Needs evaluation
golang-golang-x-net-dev 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
20.04 LTS focal
Needs evaluation
18.04 LTS bionic
Needs evaluation
16.04 LTS xenial
Needs evaluation
adsys 26.10 stonking
Needs evaluation
26.04 LTS resolute
Needs evaluation
24.04 LTS noble
Needs evaluation
22.04 LTS jammy
Needs evaluation
20.04 LTS focal
Needs evaluation
juju-core 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
16.04 LTS xenial
Needs evaluation
lxd 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
20.04 LTS focal
Needs evaluation
18.04 LTS bionic
Needs evaluation
16.04 LTS xenial
Needs evaluation
golang 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
golang-1.6 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
16.04 LTS xenial
Needs evaluation
golang-1.8 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
18.04 LTS bionic
Needs evaluation
golang-1.9 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
18.04 LTS bionic
Needs evaluation
golang-1.10 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
18.04 LTS bionic
Vulnerable
16.04 LTS xenial
Vulnerable
14.04 LTS trusty
Vulnerable
golang-1.13 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy
Vulnerable
20.04 LTS focal
Vulnerable
18.04 LTS bionic
Vulnerable
16.04 LTS xenial
Vulnerable
golang-1.14 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
20.04 LTS focal
Vulnerable
golang-1.16 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release
20.04 LTS focal
Needs evaluation
18.04 LTS bionic
Needs evaluation
golang-1.17 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy
Vulnerable
golang-1.18 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy
Vulnerable
20.04 LTS focal
Vulnerable
18.04 LTS bionic
Vulnerable
16.04 LTS xenial
Vulnerable
golang-1.20 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy
Needs evaluation
20.04 LTS focal
Needs evaluation
golang-1.21 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble
Needs evaluation
22.04 LTS jammy
Needs evaluation
20.04 LTS focal
Needs evaluation
golang-1.22 26.10 stonking Not in release
26.04 LTS resolute Not in release
24.04 LTS noble
Fixed in 1.22.2-2ubuntu0.5
22.04 LTS jammy
Fixed in 1.22.2-2~22.04.4
20.04 LTS focal
Fixed in 1.22.2-2~20.04.3
golang-1.23 26.10 stonking Not in release
26.04 LTS resolute
Needs evaluation
24.04 LTS noble
Needs evaluation
22.04 LTS jammy
Needs evaluation
golang-1.24 26.10 stonking Not in release
26.04 LTS resolute
Needs evaluation
24.04 LTS noble
Needs evaluation
22.04 LTS jammy
Needs evaluation
golang-1.25 26.10 stonking Not in release
26.04 LTS resolute
Vulnerable
24.04 LTS noble
Needs evaluation
22.04 LTS jammy
Needs evaluation
golang-1.26 26.10 stonking
Needs evaluation
26.04 LTS resolute
Needs evaluation
24.04 LTS noble
Needs evaluation
22.04 LTS jammy
Needs evaluation
golang-1.27 26.10 stonking
Needs evaluation
26.04 LTS resolute Not in release
24.04 LTS noble Not in release
22.04 LTS jammy Not in release

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Notes

mdeslaur

google-guest-agent, adsys, juju-core, lxd, containerd, golang, and google-osconfig-agent contain a vendored copy of golang-golang-x-net

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
golang-1.22

Severity score breakdown

CVSS version: CVSS v3.0

Base score 9.1 · Critical

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

References

Related Ubuntu Security Notices (USN)

Other references

Access our resources on patching vulnerabilities