Joseph Cox (MacRumors, Hacker News):

A vulnerability in Apple’s “Hide My Email” tool lets almost anyone discover a person’s real email address that is supposed to be hidden by the feature, and Apple has failed to fix it for more than a year, according to a security researcher and 404 Media’s own tests.

[…]

“Apple Hide My Email is leaking email addresses that are supposed to be hidden. We reported the issue and replication instructions to Apple over a year ago. We don’t know why it hasn’t been fixed, but we don’t feel comfortable waiting any longer. Hide My Email users deserve to know that it may be possible for attackers to discover their hidden email addresses,” Tyler Murphy, the co-founder of EasyOptOuts, which discovered and reported the issue to Apple, told 404 Media.

“Free, publicly accessible people-search sites make it easy to link an email address to other personal details, so people relying on Hide My Email for safety may be at risk,” Murphy added.

[…]

To test the issue I generated a new Hide My Email address and provided it to Murphy. Around five minutes later, he replied with my real email address linked to my Apple account which was supposed to be hidden.

Ben Lovejoy:

Murphy said that he reported the issue to Apple in June of last year, and the company told him it was looking into it. Apple said it had been fixed in March of this year, but Murphy found that wasn’t the case. He again contacted Apple, with the company saying that it would appreciate him not revealing the existence of the flaw until it had been resolved.

Apple then said it planned to address the issue in June, but since it still hasn’t been fixed[…]

Tyler Murphy:

March 19, 2026: Using the reproduction instructions from our initial report, we determined that the vulnerabilities hadn’t been fixed.

May 22, 2026: We realized that the vulnerabilities may have greater severity and scope than we thought initially and reported this to Apple. Apple never acknowledged the report of increased severity.

June 30, 2026: Apple again reported that the vulnerabilities were fixed and asked us to verify. We determined that the vulnerabilities hadn’t been fixed.

Jeff Johnson:

This is every fucking Feedback I file.

John Gruber:

Not good. Especially the “We reported the issue and replication instructions to Apple over a year ago” part.

This is becoming a pattern. At least Apple still allows third-party e-mail providers.

Nick Heer:

Very few details are available right now. I have seen speculation that the original email address is revealed when someone replies using their hidden email address, but the impression I get from Cox’s reporting is that no user interaction is necessary[…]

[…]

I am also unclear about how, as of May, the EasyOptOuts guys found the “vulnerability may have greater severity and scope” than initially reported. Ominous, though.

Previously:

• Hide My Email Moving to private.icloud.com Domain
• No Bounty for Mysk
• AirTrafficDevice: Ignored, Reluctantly Fixed, No CVE, No Bounty
• Evolution of Apple Security Bounty Program
• The Time to Fix Web Security Bugs

Update (2026-07-13): Jeff Johnson:

I don’t know whether I’ve accidentally stumbled upon that vulnerability, or perhaps in this case the Hide My Email user just messed up in some way, but I’ve definitely discovered a bizarre and troubling Hide My Email bug in Mail app (on macOS Sequoia 15.7.7).

[…]

Bizarrely, however, Mail app displayed an alert that I’ve never seen before, “This message was forwarded to you by Hide My Email,” despite the fact that I have previously received many emails from people using Hide My Email.

[…]

• Why I am seeing two different @icloud.com email addresses, one of which appears to be the sender’s unhidden address?
• Why are the To: and From: fields in my reply disabled?
• Why is my reply not from my @underpassapp.com email address but rather displayed falsely as from the sender’s @icloud.com address and really from my unrelated Apple Account address?

Update (2026-07-16): Joe Rossignol:

Apple this week was sued over a reported “Hide My Email” flaw that could expose a user’s real email address. The proposed class action lawsuit alleges that Apple violated California’s false advertising law and other consumer protection statutes by knowingly offering a feature that does not work as advertised.

This is interesting in that the June 2025 bug report is the evidence that Apple “knew” the feature didn’t work, while “Apple continued to represent to consumers that Hide My Email would actually hide users’ email.” How long are they supposed to get to fix a bug?

Update (2026-07-20): Jeff Johnson:

The misleading user interface elements in Mail app are a bug, but by themselves they’re not a vulnerability. The vulnerability is that when I send a reply to my maliciously crafted email, my Apple account email address is disclosed in the “From” field of the sent reply! In other words, the Mail app interface lies, fails to show the true sent value of the “From” field.

There are a couple of crazy aspects to this information disclosure vulnerability:

1. It does not require that the victim actually use Hide My Email! I never use it. As I mentioned in my previous blog post, I don’t even have an icloud.com email account.
2. It does not matter which of the victim’s email accounts receives the email from the attacker. If your Apple account email address is a@foo.com, but you receive a maliciously crafted email addressed to b@bar.com, Mail app will still send your reply from a@foo.com, thereby disclosing your Apple account address.

Update (2026-07-21): Juli Clover:

Apple addressed a vulnerability in Hide My Email that exposed a user's real email address, reports 404 Media. Apple told the site the issue was fully fixed in a patch released on July 3.

[…]

While the bug has now been addressed, email logs that pre-date the fix could still expose user email addresses.

Update (2026-07-22): See also: Hacker News.

Jeff Johnson:

It appears that the vulnerability I discovered, and which still occurs, is different from the vulnerability reported by others[…]

Jason Snell, on The Talk Show:

[… Apple] decides to do a big feature. The circus comes to town, they build the feature, they launch it, they leave town, and that feature sits there.

And the problem is, there’s bugs, things are broken, and in Year Two, you’re like, “You’re going to fix all the things that were broken in the thing you shipped last year, right?” And in the last decade, I would say, a lot of times what happens is they just don’t. And if you’re lucky, they’ll fix it Year Three or Year Four, […] give it a polish.

The thing that troubles me most about Apple software quality in general is the feeling like they don’t have the people to own the thing that they launch. They build the thing that they launch, and then those people go off and do something else, and nobody is maintaining and improving the thing that’s there.

Via Marcin Wichary:

I think this is spot on, and said really well. Are you honest with yourself about resourcing and focus for right after the launch and then later on? Have you really thought about worst case and best case scenarios vis-à-vis bug reports, latency, user feedback, and craft/​quality however you define it? Have you actually started to make room for those outcomes ahead of time?

For me, an ongoing tension with Apple is Finder, so central to my (and I imagine many people’s?) use of a Mac, but rewritten at some point eons ago in a new framework that caused all sorts of problems, and then pretty much abandoned like a proverbial American city’s downtown.

Revealing files in the Finder and Mail’s table view sort indicators have been broken for me since Big Sur. Disk Utility still doesn’t work as well as before its El Capitan rewrite. But these aren’t even big new features.

Jeff Johnson:

This is what happens when you release major OS updates every year: you have to keep launching new features.

Previously:

• Glow Leopard
• Child Safety Features in appleOS 27
• Will Disk Utility Ever Work Properly?
• Remaining Issues in Big Sur
• Disk Utility in El Capitan

Update (2026-06-29): Jesper:

The issue really, that Jason pins down, is that it’s so easy to use incremental development, agile development, sprints, whatever, as a method to do the wrong thing. If you have a year-long schedule, it is easier to say “I will take care of the Finder”, and within the scope of that is a number of features that need be built, but there’s also room for ongoing maintenance. Within the confines of sprint planning, within a culture that sheepishly focuses on the wrong thing, or is obsessed by following the wrong number, or worries about the internal politics of appearing to not have it together, all of a sudden the same work, scheduled into 3 week long sprints, looks like poison.

I know of plenty of organizations that make this work. That have the maturity and discipline and culture to see bugs and defects for what they are, to allocate plenty of time to them and to focus extra time on them with regular intervals.