Facebook says it's notifying ~800,000 users who were hit by a bug in Facebook and Messenger from May 29 to June 5 that unblocked some people they had blocked
this time with a new software bug that ‘unblocked’ people Amy Pollard / Slate : Facebook Accidentally Unblocked a Bunch of Blocked Users Hanna Kozlowska / Quartz : Facebook's latest screw-up unblocked people from users' blocked lists Amy Gesenhues / Marketing Land : Facebook alerts 800K users that people they'd blocked may have been unblocked the 1st week of June Matt Binder / Mashable : A major Facebook bug may have unblocked people you blocked Daniel Terdiman / Fast Company : A bug unblocked more than 800,000 Facebook and Messenger users Andy Meek / BGR : Facebook apologizes for yet another privacy screw-up David Cohen / Adweek : Facebook Caught and Corrected Yet Another Privacy-Related Bug Greg Kumparak / TechCrunch : Facebook bug temporarily unblocked people from 800,000+ block lists Rob Price / Business Insider : Facebook warns 800,000 users that it accidentally unblocked people they had already blocked Eric Abent / SlashGear : Facebook unblocking bug broke privacy settings for 800k people Sean Hollister / CNET : Here's the latest Facebook bug that (slightly) compromised your privacy Mallory Locklear / Engadget : Facebook bug caused 800,000 accounts to unblock some users Sidney Fussell / Gizmodo : Facebook Admits to Major Screw-Up That Silently Unblocked People Without Asking Bryan M. Wolfe / KnowTechie : A Facebook bug unblocked people users had previously blocked on the social site David McCabe / Axios : Facebook says bug temporarily unblocked users Mehedi Hassan / Thurrott.com : Facebook Bug Removed Some Users From Block Lists of 800,000 Users Tweets: @facebook : A bug mistakenly deleted some of these associations across Facebook and Messenger, which caused blocks to be lost. Matt Rosoff / @mattrosoff : Whoops. The difference these days, to Facebook's credit, is that the company is getting ahead and announcing that it had these kinds of problems, instead of waiting for them to leak out. Step in the right direction, I think. http://twitter.com/...
Context & Ripple Effects
The unblocking bug lands weeks after a bug set the sharing settings of 14 million users to public, making this the second disclosure in under two months where Facebook had to notify users that a software defect silently reversed their privacy choices. The company's response follows the same template both times: patch quietly, then notify affected users after the fact.
The notification covers roughly 800,000 users on Facebook and Messenger whose block lists were compromised between May 29 and June 5 — a small fraction of the user base, but one that touches the feature users rely on for personal safety rather than mere preference.
First-order effects
- Affected users must re-block anyone the bug removed from their block lists, and Facebook's apology-and-notify cycle now runs for the second time in five weeks.
- Facebook's engineering teams face renewed pressure to audit how block-state changes propagate across the Facebook and Messenger codebases, since the same defect touched both products at once.
Second-order effects
- Each successive disclosure — the 14M-public-settings bug here, and later the ~50M access-token breach and the photo API leak affecting ~6.8M users — compounds into a credibility problem that regulators and press treat as a pattern rather than isolated incidents.
- Competing platforms gain a talking point on safety controls: if blocking can silently fail, the reliability of user-controlled privacy features becomes a differentiator, not a checkbox.
Third-order effects
- If the 2018 cadence holds — repeated post-hoc notifications for defects users never knew occurred — expect regulators to push toward mandatory, faster disclosure windows for privacy-control failures, shifting bug handling from engineering hygiene to compliance obligation.
- User trust migrates toward platforms that can prove their safety features are tested as rigorously as their revenue features; 'block' becomes a product surface with an SLA rather than a simple toggle.
The trend: Facebook's 2018 string of self-disclosed bugs is turning privacy-control failures into a recurring disclosure regime, where each incident raises the bar for how quickly platforms must notify users and regulators.