Last updated: July 5, 2026 at 9:01 AM UTC
All 557 Vulnerability 199 Breach 106 Threat 245 Defense 7
Tag: use-after-free (4 articles)Clear

Bad Epoll Linux kernel flaw lets any local user gain root, including on Android

A newly disclosed Linux kernel vulnerability called Bad Epoll lets an ordinary user with no special privileges take full control of a machine as root, and it affects Linux desktops, servers, and Android. Tracked as CVE-2026-46242, the flaw is a use-after-free in epoll, a core Linux feature for watching many files or connections at once that programs and browsers rely on and cannot simply turn off. Two parts of the kernel try to free the same object at once, letting an attacker corrupt kernel memory and climb to root. It is a race-condition bug, harder to exploit than recent deterministic Linux flaws, but a working exploit exists and a fix is available.

Check
Identify Linux servers, workstations, and Android devices in your environment and check their kernel versions against the Bad Epoll fix, prioritizing multi-user systems and anything where untrusted users can run code.
Affected
Linux desktops, servers, and Android devices on kernels without the Bad Epoll fix (CVE-2026-46242); any local user, or code already running with low privileges, can exploit the flaw to gain root.
Fix
Apply the kernel updates that fix Bad Epoll as they reach your distributions and Android devices; there is no workaround, since epoll cannot be disabled, so patching is the only real mitigation.

Eight-year-old Samsung KNOX kernel flaw exposed Galaxy S9 through S25

Researchers at LucidBit Labs detailed an eight-year-old use-after-free flaw in the kernel of Samsung's KNOX security framework that affected a huge range of Galaxy devices, from the Galaxy S9 to the S25, across A-series and both Exynos and Qualcomm models. The bug (CVE-2026-20971) sits in a race between two KNOX components that verify process integrity, and a malicious app could exploit it to corrupt kernel memory and potentially take full control of the device. Samsung quietly fixed it in its January 2026 security update. Exploitation requires local access and some user interaction, but a lost, borrowed, or stolen phone makes that realistic.

Check
Confirm that Samsung Galaxy devices in your environment have installed the January 2026 or later security update, and identify any older or unmanaged Galaxy phones that may still be missing it.
Affected
Samsung Galaxy devices from the S9 through S25, plus A-series models on both Exynos and Qualcomm chips (CVE-2026-20971), that have not applied the January 2026 security update.
Fix
Apply the January 2026 or later Samsung security update to all Galaxy devices, enforce update compliance through mobile device management, and retire devices no longer receiving security patches.

Autonomous AI tool finds 2-year-old Redis use-after-free RCE CVE-2026-23479 - most cloud Redis runs passwordless, exploit public

Team Xint Code has disclosed CVE-2026-23479, a use-after-free remote code execution flaw in Redis that sat unnoticed in every stable branch from 7.2.0 until the May 5 fixes - over two years. The bug lives in unblockClientOnKey(), which keeps using a client pointer after processCommandAndResetClient() can free it. Exploitation needs an authenticated session, but Wiz's analysis finds Redis in most cloud environments with the majority running passwordless, where the default user already holds every privilege the exploit chain requires. The published exploit leaks a heap pointer via Lua, reclaims a freed client with a fake structure, and overwrites a GOT entry to repoint strcasecmp() at system(). NVD rates it 8.8.

Check
Inventory Redis instances and confirm version is past the May 5 fix. Identify passwordless or internet-reachable deployments. Audit for unexpected Lua EVAL activity and child processes spawned by redis-server.
Affected
Redis 7.2.0 through the May 5 fixes (over two years of stable branches). Exploitation needs an authenticated session, but most cloud Redis runs passwordless with the all-privileged default user.
Fix
Upgrade Redis to the patched release. Require authentication and strong ACLs, bind to localhost or private networks, never expose Redis to the internet. Enable full RELRO when building images.

Critical 'Dead.Letter' use-after-free in Exim mail server enables unauthenticated remote code execution over TLS - GnuTLS builds only (CVE-2026-45185)

Exim, the open-source mail transfer agent that ships as default on Debian and powers a large slice of internet mail, has a critical use-after-free in how it parses message bodies sent with the BDAT chunking extension over TLS. The flaw, CVE-2026-45185 (CVSS 9.8) and nicknamed Dead.Letter by discoverer XBOW, triggers when a TLS connection closes via close_notify mid-BDAT and Exim then processes one more cleartext byte. That byte gets written into already-freed memory, corrupting the heap, and XBOW turned it into an unauthenticated RCE primitive. Only Exim builds compiled with USE_GNUTLS=yes are affected; OpenSSL builds are not.

Check
Check installed Exim version and verify how the package was built (GnuTLS vs OpenSSL). Look for EHLO responses on TCP/25, /465, and /587 that advertise both STARTTLS and CHUNKING from any internet-facing MTA you own.
Affected
Exim versions 4.97 through 4.99.2 compiled with USE_GNUTLS=yes (the Debian default). Affects internet-facing MTAs that advertise both STARTTLS and CHUNKING (BDAT) - common on ISPs, shared hosting, university mail, and small relays.
Fix
Upgrade to Exim 4.99.3 or the matching distribution package (Debian DSA-6265-1 covers oldoldstable, oldstable, stable; Ubuntu 24.04 LTS shipped on May 12). Where patching is blocked, rebuild against OpenSSL or restrict SMTP ports to known peers.