eMudhra to exit TLS after weak intermediate keys blocked
October 23: Cisco published an informational advisory urging emergency distrust of eMudhra root and intermediate authorities, and said unlisted products are not affected.
Browsers and vendors blocked eight weak eMudhra intermediates; the company revoked them and is leaving SSL/TLS issuance, with no confirmed attacks.
Private keys for eight eMudhra intermediate CAs were tiny P-384 values that researchers recovered from public certificates in under a second. Wayne reported the keys on October 17, 2026, after a flawed April 30, 2025 ceremony; Mozilla and Scott Helme independently recovered them the same day. Six intermediates were for TLS and two for code signing; all were cross-signed by Sectigo and chained to major browser roots. Chrome, Firefox, Apple, and Microsoft blocked them by October 20, and eMudhra revoked them and said it will stop issuing SSL/TLS certificates. CSO Online reports eMudhra says the intermediates issued no end-entity certificates, while Help Net Security and Security Brigade cite about 30,000 needing migration; Chrome and Talos report no confirmed malicious use.
- Six TLS and two code-signing intermediates used single-byte P-384 private keys.
- Chrome’s CRLSet was in place by 19:45 UTC on October 17.
- Go 1.27.3 and 1.26.10 distrust the keys under CVE-2026-111943.
- Firefox 158.0.1 and two ESR builds ship the OneCRL block.
- Affected intermediates were not due to expire until April 2040.
- Google plans to remove emSign ECC Root CA – G3 on October 27.
Timeline
dated events in the reporting · oldest first- Apr 30, 2025Weak keys created in eMudhra ceremony · Help Net Security
- Oct 17, 2026Wayne reports keys; Chrome and Firefox block them · The Hacker News
- Oct 18, 2026eMudhra revokes the eight intermediates · Help Net Security
- Oct 20, 2026Microsoft blocks certificates; Mozilla removes signing root · Cyber Security News
- Oct 22, 2026eMudhra says it will leave SSL/TLS issuance · The Record
- Oct 23, 2026Cisco advisory calls for emergency distrust · Cisco Security Advisories
What each outlet adds
beyond the shared facts- The Hacker NewsExact UTC block times and Firefox CVE-2026-113470
- CSO OnlineNo end-entity certificates claim versus 30,000 migration estimate
- LobstersListed private scalars and May 2025 Sectigo cross-signs
- The RecordVoluntary exit, revenue share, and April 2040 expiry
- Cisco Security AdvisoriesOctober 23 informational distrust advisory for Cisco products
- Products
- uvpipcertifiChromeFirefoxNSSwebpki-rootsOneCRLTLS/SSL certificatesNext-Gen Trust SecurityemSign ECC Root CA – G3eMudhra intermediate certificates
- Organizations
- eMudhraMozillaMicrosoftAppleCloudflareChrome Root ProgramMajor browser and operating system vendorsGoogleCisco TalosCERT-INSectigo
- Countries
- IndiaUnited StatesNetherlands
Coverage
oldest first · one row per article · UTC- · 5d ago
Lobsters · securityFirst report
Mozilla blocks eight compromised eMudhra intermediate certificates
OneCRL reached standard Firefox users in under three hours; 158.0.1 and two ESR builds cover the rest.
- · 5d ago
oss-security
Mozilla alerts Firefox users after eMudhra intermediate compromise
The notice reached the distros list a day before this oss-security forward and points to a Mozilla security post.
- · 5d ago
The Hacker News
Eight eMudhra intermediate CA keys compromised; browsers block them
Chrome and Firefox blocked the TLS intermediates within hours of an October 17 report, and no website certificate chaining to them was in Certificate Transparency beforehand.
- · 5d ago
Chrome and Firefox drop eMudhra root after certificate compromise
Whether Edge, Internet Explorer, cURL, and other private root stores still trust eMudhra is unconfirmed.
- · 5d ago
Cyber Security News
eMudhra intermediate CA key compromise triggers browser blocks
Eight intermediates chaining to major browser roots were blocked; attacks on users are not confirmed.
- · 5d ago
Mozilla opens its eMudhra intermediates tracking bug to the public
Alan Coopersmith says restrictions on Mozilla bug 2083449 were removed on October 20.
- · 4d ago
Dark Reading
Tech giants block eMudhra certificates tied to 8 compromised keys
Six keys issued website TLS certificates and two were for code signing; fraudulent issuance is unconfirmed.
- · 4d ago
Simon Willison
Eight eMudhra intermediate CA private keys compromised
The intermediates chain to roots in major browser programs, so bundled trust stores need updates.
- · 4d ago
BleepingComputer
Mozilla, Google and Apple block compromised eMudhra certificates
Eight April 2025 intermediates used private keys smaller than 256; no abuse is evidenced, but many trust stores needed updates.
- · 4d ago
GBHackers
Weak eMudhra keys expose eight trusted intermediate certificates
All eight P-384 private keys were integers below 256 and could be recovered from public certificate data.
- · 4d ago
NSS 3.131.1 drops emSign certs amid eMudhra questions
Solar Designer asks whether another certificate still cross-signs the compromised intermediates.
- · 4d ago
oss-security reply praises handling of eMudhra intermediate compromise
The note suggests other CA root and intermediate keys should be checked for weak private keys.
- · 4d ago
CSO Online
Google and Mozilla revoke eight eMudhra intermediates after weak keys
Keys were trivially recoverable from public certificates; Google saw no chaining TLS certificates in CT logs before blocking.
- · 4d ago
SecurityWeek
Browsers block eMudhra intermediate CAs with recoverable private keys
Eight April 2025 intermediates used near all-zero keys; browsers blocked them between October 17 and October 20.
- · 4d ago
Lobsters · security
eMudhra intermediate CA keys were single-byte and factorable
Eight April 2025 intermediates, also cross-signed by Sectigo, used P-384 private keys of one byte.
- · 4d ago
Help Net Security
eMudhra CA signing keys were so weak anyone could recover them
Eight intermediates from an April 2025 ceremony used keys under 256; browsers blocked them, and about 30,000 customer certificates need replacement.
- · 4d ago
badkeys author says he already scans CCADB certs for weak keys
Hanno Böck has not yet added checks for small ECDSA keys and plans a later write-up.
- · 4d ago
Gutmann cites Fermat checks for RSA keys with close primes
On the eMudhra intermediates thread, he says Let's Encrypt rejects public keys whose primes are too close.
- · 3d ago
Cisco Talos
Weak eMudhra intermediate keys can impersonate sites; vendors block them
Go 1.27.3 and 1.26.10 distrust eight weak intermediates as CVE-2026-111943; Talos reports no malicious use yet.
- · 3d ago
Firefox 153 ESR still trusts Comodo AAA, list reply says
Jakub Wilk says his Firefox 153 ESR still trusted the Comodo AAA certificate despite Mozilla bug 1957685.
- · 3d ago
CyberScoop
eMudhra ends certificate business after weak private keys cracked
Eight intermediate keys were integers below 256, one of them 4; major browsers blocked the certificates within days.
- · 3d ago
Palo Alto Unit 42
eMudhra Intermediate CA Private Keys Compromised
Eight eMudhra intermediate CA private keys generated with insufficient randomness were compromised, enabling private key derivation and unauthorized TLS certificate signing.
- · 3d ago
The Record
eMudhra exits certificate business after weak intermediate keys
Eight intermediate keys were trivial values; browsers blocked them, and the firm says nothing was breached.
- · 2d ago
Cisco Security Advisories
eMudhra intermediate CA keys can be brute-forced, Cisco says
A researcher showed eight intermediate private keys from an April 2025 ceremony can be recovered in seconds.
Vulnerabilities in this story
All| CVE | Vulnerability | CVSS | EPSS | Signals | Published |
|---|---|---|---|---|---|
| CVE-2026-111943 | On most platforms, Go uses the given system root certificates | — | <1% | PoC | |
| CVE-2026-113470 | Cryptographic issue in the Security Block-lists, Allow-lists, and other State component | 5.4 | — |