CVE

On July 22, Qualys published a Linux kernel advisory that anyone running shared hosting on a RHEL-family system should read before doing anything else: CVE-2026-64600, nicknamed RefluXFS. It is a local privilege escalation to root in the Linux kernel’s XFS filesystem, and the proof-of-concept Qualys published strips the root password from /etc/passwd in seconds — starting from an ordinary, unprivileged local account. The vulnerability has been sitting in the kernel since version 4.11, released in 2017. Nine years of shared hosting servers, VPS instances, and cloud nodes, quietly exposed. ...

F5 patched CVE-2026-42533 on July 15. If you run nginx, this one deserves your attention before the proof-of-concept code drops — and there is a countdown on that. What the flaw is The vulnerability is a heap buffer overflow (CWE-122) in nginx’s script engine — the component that assembles output strings from configuration directives at request time. It surfaces under a specific configuration pattern: a map block using regex matching, where the map’s output variable appears in a string expression after a numbered capture variable ($1, $2) from an earlier regex match. ...

A working proof-of-concept for CVE-2026-43499, nicknamed GhostLock, went public on July 7, 2026. It hands any unprivileged local user a root shell in about five seconds, and it works from inside a container to escape to the host. If you run Linux servers — shared hosting, VPS, or bare metal — this is the one to patch before anything else this week. What GhostLock is The bug lives in kernel/locking/rtmutex.c, on the futex priority-inheritance (PI) path. When the kernel handles a FUTEX_CMP_REQUEUE_PI requeue and detects a deadlock cycle, it rolls back with -EDEADLK by calling remove_waiter(). The problem: that helper clears pi_blocked_on on the wrong thread — not the sleeping thread it should be cleaning up, but the currently running task. That leaves a live thread holding a dangling pointer into already-freed kernel stack memory. Stack use-after-free. ...

PHP pushed maintenance releases for its two active development branches on July 1–2, 2026. PHP 8.5.8 and 8.4.23 are out. Neither is a major feature release, but they fix issues that can cause real harm to production servers. If you’re hosting PHP applications, patch now. The headliner: CVE-2026-14355 The most critical fix in both releases is CVE-2026-14355, addressing memory corruption in openssl_encrypt() when used with the AES-WRAP-PAD cipher mode (bug GH-22187). Specifically, the internal zend_mm_heap gets corrupted during this operation. Heap corruption is the kind of bug that ranges from “your process crashes at random” to “someone potentially executes arbitrary code,” depending on how the application uses the function and what an attacker can control. If you use PHP’s OpenSSL extension for encryption — and many applications do — this one warrants immediate attention. ...

On June 25, 2026, JFrog Security Research published a working exploit walkthrough for a Linux kernel privilege escalation they named DirtyClone. Tracked as CVE-2026-43503 with a CVSS score of 8.8, it lets any local user on an unpatched system escalate to root — and the attack leaves nothing on disk for forensic tools to find. That combination should get a hosting operator’s attention. What the Bug Is The flaw lives in __pskb_copy_fclone(), a kernel function that copies network packets internally. When a packet is cloned, this function — and a handful of related fragment-transfer helpers — drops a safety flag called SKBFL_SHARED_FRAG. That flag marks packet memory as shared with a file on disk. Once it’s gone, the kernel no longer treats the memory as read-only, and an attacker can write to it. ...

If you’re running Exim on Debian or Ubuntu and haven’t patched in the past five weeks, there’s a reasonable chance your mail server is remotely exploitable by anyone who can open a TLS connection to port 25. No credentials required. No special tooling. Standard SMTP commands. CVE-2026-45185, nicknamed Dead.Letter, is a use-after-free vulnerability in Exim’s BDAT message parsing path. CVSS score: 9.8 Critical. Fixed in Exim 4.99.3, released May 12, 2026. If you haven’t checked your version since then, now would be a good time. ...

Apache HTTP Server 2.4.68 came out on June 8, 2026 — the first point release since 2.4.67 in early May, and per the project’s own download page, it’s “recommended over all previous releases.” If you run your own LAMP stack, this is the patch to schedule this week. What’s actually in it The public CVE list on httpd.apache.org hasn’t fully caught up to the release yet, but the individual disclosures have already landed on oss-security and in distro security trackers. Three are worth knowing about specifically. ...

On June 3, 2026, researcher Quang Luong published a remote denial-of-service exploit called the HTTP/2 Bomb that can exhaust tens of gigabytes of server memory using nothing more than a home internet connection. The vulnerability was posted to oss-security the same day and affects nginx, Apache httpd, Microsoft IIS, Envoy, and Cloudflare Pingora in their default HTTP/2 configurations. The CVE identifier CVE-2026-49975 was assigned to the Apache httpd variant. What the attack does The exploit chains two techniques, both of which have been individually documented for roughly a decade, in a way that no prior public research had combined against these servers. ...

On 5 May 2026, the Dovecot team published security advisory OXDC-2026-0002, covering five vulnerabilities fixed in OX Dovecot CE 2.4.4 (and Pro 3.1.5). If you are running Dovecot CE 2.4.3 or earlier, this is your prompt to upgrade. What’s in the advisory CVE-2026-27851 — SQL/LDAP injection via variable expansion (CVSS 7.4) The most serious of the five. When the safe filter is used in Dovecot’s variable expansion (lib-var-expand), it incorrectly treats all subsequent pipelines on the same string as safe too. The result: attacker-controlled data can bypass escaping and land unmodified in SQL or LDAP queries used for authentication. No public exploit exists yet, but CVSS 7.4 with a network attack vector and no required privileges is not something to sit on. If you cannot upgrade immediately, the workaround is to avoid the safe filter in your configuration until you can. ...

MariaDB patched CVE-2026-35549 on April 3, 2026. Seven weeks later, the fixed packages haven’t landed in the official repositories of RHEL 8, 9, and 10, Ubuntu LTS releases, or CentOS 8. If you’re running distro-packaged MariaDB and have the caching_sha2_password authentication plugin in use, your database server can be crashed by any authenticated user with a single oversized packet. What the Bug Is The vulnerability lives in the caching_sha2_password authentication plugin — MariaDB’s compatibility layer for the plugin MySQL 8.0 made default. When processing an authentication request, the plugin calls sha256_crypt_r, which allocates memory via alloca(). Unlike malloc(), alloca() grabs memory directly from the stack with no size check whatsoever. Feed it a packet that’s large enough, and the function attempts to allocate more stack space than exists, causing the server process to crash immediately. ...