WARNING--eMudhra's Eight Cracked Certificates Have Been Blocked on Apple Devices Since October 19, but the Mac's Built-In curl, git and python3 Still Trust Them Until /etc/ssl/cert.pem Is Fixed

2026October 22, 2026Macs Only!Security
Five Apple devices in a row on a white background: an Apple Vision Pro headset at the left, an open MacBook showing Image Playground with a photo of a pelican, an iPad standing in front of it with an Allowed Apps dialog, an iPhone showing a Maps itinerary, and an Apple Watch with its app grid at the right.
Photo: Apple · Five Apple devices in a row on a white background: an Apple Vision Pro headset at the left, an open MacBook showing Image Playground with a photo of a pelican, an iPad standing in front of it with an Allowed Apps dialog, an iPhone showing a Maps itinerary, and an Apple Watch with its app grid at the right.

Eight eMudhra intermediate certificates whose private keys anyone can recover from the certificates themselves have been blocked on Apple devices since October 19, according to Dennis Jackson's incident page, published by the Mozilla cryptography engineer. The same page says the Mac's own curl, git, python3, perl, ruby and openssl still trust them, because they check /etc/ssl/cert.pem "without checking revocation, and that file has not been updated." Safari is covered; Terminal is not, until Apple updates that file or you do.

Eight private keys that were one byte long

Mozilla's incident report says that on October 17 at 20:06 UTC it received a report, forwarded by the Chrome root program from a researcher named Wayne, that the private keys of eight eMudhra intermediate certificates had been compromised. It says "the 8 impacted keys all used integers less than 256. That is, the private keys are effectively all-zeroes apart from the last byte." The Hacker News reported on October 20 that researcher Scott Helme recovered all eight on his laptop in under a second, and that one of the keys is the number 4. eMudhra's statement traces the keys to a key generation ceremony on April 30, 2025: "a key wrap/unwrap step produced a second, weak set of keys alongside the original strong keys. The weak keys were the ones published to the browser root stores." The company says seven of the eight were never used in production and that the eighth "had not issued a single certificate." Mozilla's timeline has eMudhra revoking all eight on October 18 at 09:38 UTC.

What Apple blocked, and what it left

Jackson's page says the certificates "have been blocked in Firefox and Chrome since the 17th of October, in Apple devices since the 19th and on Microsoft platforms since the 20th," and that all four remediated it "through their tools for distributing revocation information." The two roots its workaround removes, emSign ECC Root CA - G3 and, through the Sectigo cross-signs the page lists, AAA Certificate Services, are both on Apple's root certificate list for macOS 26 and iOS 26, published December 17, 2025. The built-in command-line tools verify against /etc/ssl/cert.pem, which Apple has not changed, and 9to5Mac, reporting the gap on October 21, calls it "something that Apple is likely to be able to fix in an upcoming security update." As of October 22, Apple's security releases page has no entry newer than the September 28 updates and nothing about certificates. Jackson's page adds that the certificate transparency logs hold no entries for these intermediates since April 2025, "indicating that CT-enforcing clients like Firefox, Chrome, Edge and Safari could not have been attacked." For clients outside the browser, it does "not know if attackers exploited the flawed key generation to target these clients."

What to do now

  1. Test your Mac. In Terminal, run curl https://dv-g3b-emudhra.we-have-a-problem.com/ and curl https://dv-g3b-aaa-emudhra.we-have-a-problem.com/. Jackson's page says "a certificate error means the client does not trust the compromised intermediates." A page that loads means your curl still does.
  2. Edit the bundle if you depend on the built-in tools. The page's workaround copies /etc/ssl/cert.pem to cert.pem.bak and runs one awk command that drops the AAA Certificate Services and emSign ECC Root CA - G3 entries, then a second command that points the built-in pip3 at the fixed file through sitecustomize.py. Copy both commands from the page and keep the backup.
  3. Update what carries its own roots. Jackson's table of patched versions lists curl's own CA bundle dated October 20, Homebrew's ca-certificates at 2026-09-25_1, Node.js 22.23.4, 24.22.1 and 26.12.1, and Python certifi 2026.10.19. curl's CA extract page shows the October 20 bundle holding 118 certificates against 121 on September 25. Firefox 158.0.1, released October 20, builds the block list into the browser itself.

Then and now

On October 22, 2001, our note on the Internet Explorer 5.1 Security Update recorded a fix arriving through the Mac OS X 10.1 Software Update panel for "the security hole of IE launching downloaded files after decoding them." Earlier that year, our March 26, 2001 Dark Side item relayed that VeriSign had given certificates in Microsoft's name to an impostor, "an honest mistake" in the words of the article it quoted. Our October 21, 2002 note on the Office 98 SSL Security Updater quoted Microsoft on a flaw that let "an attacker who had a valid security certificate to issue an invalid subordinate certificate that would appear to be valid." Then the browser was the hole and Apple shipped the patch; now the browser is fixed by a switch nobody has to install, and the hole is the toolkit underneath it. We have not run the workaround ourselves. Apple closed Safari in two days, and it should not leave a file every developer's Mac relies on to a volunteer's awk script. [Macs Only!]

Sources

  1. Dennis Jackson, “eMudhra Intermediate CA Compromise” accessed Oct 22, 2026The page dated 20th October 2026, "Site published by Dennis Jackson" with "many contributors from the community": "The private keys of eight eMudhra intermediate CA certificates have been compromised. They chain to roots trusted by the Mozilla, Microsoft, Apple and Chrome root programs"; Wayne reported it to the Root Program Teams on the 17th of October; "The certificates have been blocked in Firefox and Chrome since the 17th of October, in Apple devices since the 19th and on Microsoft platforms since the 20th"; remediated by Mozilla, Microsoft, Apple, and Chrome "through their tools for distributing revocation information"; the test commands curl https://dv-g3b-emudhra.we-have-a-problem.com/ and curl https://dv-g3b-aaa-emudhra.we-have-a-problem.com/ and "A certificate error means the client does not trust the compromised intermediates"; no certificate transparency entries since April 2025, "indicating that CT-enforcing clients like Firefox, Chrome, Edge and Safari could not have been attacked" and "We do not know if attackers exploited the flawed key generation to target these clients"; "impacted-intermediates.json lists the eight intermediates and their Sectigo cross-signs"; "anyone can recover them from the certificates"; the macOS section: "macOS blocks the compromised intermediates, but the built-in curl, git, python3, perl, ruby, and openssl verify certificates against /etc/ssl/cert.pem without checking revocation, and that file has not been updated", the cp of /etc/ssl/cert.pem to /etc/ssl/cert.pem.bak and the awk command removing the CN=AAA Certificate Services and CN=emSign ECC Root CA - G3 entries, and the sitecustomize.py command setting PIP_CERT for the built-in pip3; the patched-versions table rows curl CA bundle 2026-10-20, Homebrew ca-certificates 2026-09-25_1, Node.js 22.23.4, 24.22.1, 26.12.1, Python certifi 2026.10.19; accessed October 22, 2026.
  2. Mozilla, “2083449 - eMudhra: Private key compromise of Intermediate Certificates” accessed Oct 22, 2026Dennis Jackson's incident report: "On 17th October @ 20:06 UTC, Mozilla received a report to certificates@mozilla.org, forwarded by the Chrome Root program, from Wayne, that the private key of 8 eMudhra Intermediate certificates have been compromised"; "The 8 impacted keys all used integers less than 256. That is, the private keys are effectively all-zeroes apart from the last byte"; "18th October @ 09:38 UTC: eMudhra marked the 8 impacted certificates as revoked (reason: caCompromise)"; accessed October 22, 2026.
  3. eMudhra, “eMudhra Statement on Recent Certificate Security Incident” accessed Oct 22, 2026First published 20 October 2026, last updated 21 October 2026: eight intermediate CAs created in a Key Generation Ceremony on April 30, 2025; "During the ceremony, a key wrap/unwrap step produced a second, weak set of keys alongside the original strong keys. The weak keys were the ones published to the browser root stores"; "Seven of the eight intermediates were never used in production. The one that was in production had not issued a single certificate"; accessed October 22, 2026.
  4. The Hacker News, “Eight eMudhra CA Keys Compromised, Triggering Emergency Fixes Across Browsers and Software” accessed Oct 22, 2026October 20, 2026, Swati Khandelwal: Scott Helme "recovered all eight private keys from the public certificates on his laptop in under a second, that one of them is the number 4 and the rest are also whole numbers below 256"; "Apple blocked them on October 19"; accessed October 22, 2026.
  5. Apple Support, “List of available root certificates in iOS 26, iPadOS 26, macOS 26, tvOS 26, visionOS 26 and watchOS 26 - Apple Support” accessed Oct 22, 2026Published December 17, 2025; the rows "AAA Certificate Services", issued by AAA Certificate Services, RSA, 2048 bits, and "emSign ECC Root CA - G3", issued by emSign ECC Root CA - G3, ECDSA, 384 bits; accessed October 22, 2026.
  6. 9to5Mac, “Apple blocks web certificates that could be used by scammers, but Mac vulnerability remains - 9to5Mac” accessed Oct 22, 2026October 21, 2026, 5:16 a.m. Pacific, Ben Lovejoy: Apple blocked eight web security certificates; Dennis Jackson described as a Mozilla cryptography engineer; Safari and other browsers block them while macOS's built-in /usr/bin/curl may continue trusting them; "it's something that Apple is likely to be able to fix in an upcoming security update"; accessed October 22, 2026.
  7. Apple Support, “Apple security releases - Apple Support” accessed Oct 22, 2026As read on October 22, 2026: the newest entries are the September 28, 2026 releases (iOS 27.0.1 and iPadOS 27.0.1, iOS 26.7.1 and iPadOS 26.7.1, macOS Golden Gate 27.0.1, macOS Tahoe 26.7.1, macOS Sequoia 15.8.1, watchOS 27.0.1, visionOS 27.0.1); no entry dated October 17 to 22, 2026 and none mentioning certificates or eMudhra.
  8. curl, “curl - Extract CA Certs from Mozilla” accessed Oct 22, 2026The CA bundle list: 2026-10-20 with 118 certificates, 2026-09-25 with 121 certificates; the bundle is converted from Mozilla's certificate store; accessed October 22, 2026.
  9. Mozilla, “Firefox 158.0.1, See All New Features, Updates and Fixes” accessed Oct 22, 2026Released October 20, 2026: "Mozilla blocked compromised eMudhra intermediate certificates via OneCRL on October 17th. The blocks were distributed to clients via Remote Settings the same day. This update contains the updated OneCRL block list, ensuring clients will block the compromised certificates even if RemoteSettings is disabled by policy or otherwise unavailable in the user's network environment"; accessed October 22, 2026.
  10. Apple Newsroom, “Apple unveils next generation of Apple Intelligence, Siri AI, powerful parental controls, and an expansive set of software improvements - Apple” accessed Oct 22, 2026June 8, 2026: the press picture Apple captions "Apple Vision Pro, MacBook, iPad, iPhone, Apple Watch, and Apple TV are pictured"; accessed October 22, 2026.

Then and now

All pairings

In October 2001 Apple pushed an Internet Explorer security fix through Software Update; in October 2026 it blocked eight cracked certificates in two days and left the Mac's curl trusting them.

Also on October 22, other years

Every October 22 since 1997

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