Oracle GraalVM for JDK

eMudhra: the private keys of eight intermediate CA certificates were trivially recoverable, so anyone could forge trusted HTTPS certificates; browsers block them, clients with their own trust store or no revocation checking need an update (CVE-2026-111943 in Go)

On 2026-10-17 a researcher reported to the Chrome Root Program, and Mozilla received a report the same day, that the private keys of eight eMudhra subordinate CA certificates were compromised: the keys were generated with insufficient randomness, which lets anyone forge trusted HTTPS certificates to impersonate any website against clients that have not removed trust in those CAs (Google, 2026-10-20; Mozilla, 2026-10-20). BleepingComputer, citing Mozilla's incident report, says all eight were P-384 keys generated in April 2025 with values below 256, so testing 256 numbers recovers a key, and that eMudhra blames a key-generation script error and found no evidence of end-user certificates (BleepingComputer, 2026-10-20). Google reports that no certificates chaining to the six TLS intermediates were logged to Certificate Transparency before it blocked them, so CT-enforcing clients such as Chrome could not have been attacked (Google, 2026-10-20); the tracker adds that many clients outside browsers do not enforce CT and that it is not known whether attackers used the flaw against them (Dennis Jackson, 2026-10-20).

Chrome blocked the intermediates on 2026-10-17, Firefox through OneCRL the same day, Microsoft platforms on 2026-10-20 and Apple devices on 2026-10-22, and eMudhra revoked all eight (Dennis Jackson, 2026-10-20; BleepingComputer, 2026-10-20). Google removed the root that signed them, emSign ECC Root CA - G3, from the Chrome Root Store, with the removal expected to reach devices on 2026-10-27, after which some legitimate certificates chaining to it will stop working in Chrome (Google, 2026-10-20); Mozilla removes the signing root from NSS 3.131.1 to protect applications that use its trust store without OneCRL (Mozilla, 2026-10-20). Go 1.27.3 and 1.26.10 filter chains that contain the intermediates in crypto/x509, tracked as CVE-2026-111943 (Go team, 2026-10-20).

Standalone Java runtimes keep their own trust store (OpenJDK, 2026-10-21). Oracle's Security Alert of 2026-10-21 for CVE-2026-91403 (CVSS 3.1 9.1, component JSSE, remotely exploitable without authentication through the component's APIs, for example a web service that supplies data to them) provides Java updates that distrust the impacted eMudhra intermediate CA certificates (Oracle, 2026-10-21), and the OpenJDK advisory of the same day says a standalone OpenJDK runtime likely contains the compromised certificates and should be updated as soon as possible (OpenJDK, 2026-10-21). If a runtime cannot be updated, OpenJDK gives two alternatives: replace the runtime's blocked.certs file (blacklisted.certs on Java 8) with the vendor's version, or enable revocation checking with -Dcom.sun.net.ssl.checkRevocation=true and -Dcom.sun.security.enableCRLDP=true for TLS clients, and use jarsigner -verify -revcheck -strict for signed JARs on JDK 17 and later; the step is repeated for every installed runtime (OpenJDK, 2026-10-21). OpenJDK packages from Arch Linux, Debian, Devuan, Fedora, Gentoo, Oracle Linux, Red Hat Enterprise Linux and Ubuntu use the operating system's certificates, so updating those suffices, which is not true of the FreeBSD and Homebrew packages (OpenJDK, 2026-10-21). NCSC.ch published an advisory on 2026-10-22 and lists the exploitation status as unknown (NCSC.ch, 2026-10-22).

Triage: a site that still chains to emSign ECC Root CA - G3 failing in Chrome after 2026-10-27 is the announced root removal, not an attack (Google, 2026-10-20).