On October 2, 2026, The Firebase Blog published Google's account of an outage four days earlier. On September 28, 2026, it says, "a routine configuration cleanup unexpectedly caused a large number of applications on iOS and other Apple platforms using the Google Analytics for Firebase (GA4F) SDK to crash." Parts of the post follow, not the whole.
A Flag Removed, a Pointer Left
The post says the SDK uses remote configuration flags "in a manner intended to improve reliability," sometimes "as a kill switch in case a feature contains a bug that we did not catch during testing." Over time it gathers flags that are no longer needed, and those are marked for cleanup. In this case the team removed a flag, "a 2-line change," but "failed to remove a pointer to that flag in the SDK."
"When the SDK fetched the missing flag, this resulted in a fatal error, causing active users to experience a one-time crash, after which the SDK fell back to the previous config." The backend served the invalid configuration "for 2 hours and 11 minutes." And because the kill switch mechanism is itself released globally, the post says, "the errant config was released to a wide population of apps." Further on, the post says, "The SDK missed validating that a flag's name was not nil, ultimately causing the crash."
What the Checks Saw
The engineering team "was alerted to this issue within 20 minutes of rollout through a variety of channels," the post says, identified the change, and rolled it back. Developers may have kept seeing crash reports after the fix, because crash reports "are queued locally and only uploaded the next time a user successfully opened the app." The post says no device was observed entering a permanent crash loop.
"Throughout the outage, both the Firebase and Google Ads status dashboards remained green," the post says. "Because these dashboards rely primarily on server-side health metrics, they did not register client-side SDK crashes." The Firebase dashboard has no entry of its own for the analytics SDK and links out to the Ads dashboard instead, so updating both "required manual intervention that took several hours." The post says the team introduced a banner to the Firebase console, followed by status dashboard updates the next morning and evening.
On the pipeline, the post says, "Existing tests passed on the change that resulted in the invalid configuration."
What Google Commits To
For the SDK, the post commits to a patch "in the next week to validate every incoming server payload strictly." If a flag is corrupt or missing a required field, the post says, "the SDK will safely ignore that specific flag and fall back to its cached defaults," and the team is reviewing all other Firebase iOS and Android SDKs to ensure "similar parsing weaknesses do not exist."
For the dashboards, the team says it is working to "integrate SDK-related outage information into our status dashboards," to streamline the manual update process and to improve how the analytics SDK is represented in the Firebase dashboard. For the pipeline, it is adding automated validation scripts to its configuration pipelines and pre-submit tests. "If a flag cleanup or schema change results in broken dependencies or orphaned identifiers, the pipeline will automatically block the release before the change can be merged." The new check looks for broken dependencies and orphaned identifiers. What catches a change that breaks in a way no script yet looks for?
On rollouts, the post says, "Deploying configuration changes to a broad segment of our global customer base too quickly introduces unnecessary risk," and the team is "prioritizing investments in our configuration deployment process to improve our monitoring and rollout phasing."
Sources
- Google (The Firebase Blog). Google Analytics for Firebase iOS SDK outage on September 28, 2026. 2 October 2026. incident report