Use-After-Free

Summary A race condition in the Windows Print Spooler service leads to a use-after-free that allows an authenticated attacker to escalate privileges to SYSTEM. The vulnerability requires the attacker to win a race during spooler component processing, but successful exploitation grants full control of the affected system. Microsoft rates exploitation as More Likely on newer Windows versions. This vulnerability was discovered by Aretiq AI and responsibly disclosed to Microsoft, who addressed it in the September 2026 Patch Tuesday security updates. Microsoft has credited ECooper with Aretiq.AI for reporting this vulnerability in their security advisory. ...

1. Overview A use-after-free vulnerability exists in ISC BIND 9’s DNS-over-HTTPS (DoH) implementation. When a DoH response has been sent, the response buffer is freed but a dangling pointer (socket->h2->wbuf) is left pointing to the freed memory. If a client floods HTTP/2 SETTINGS frames that change INITIAL_WINDOW_SIZE, the nghttp2 library re-evaluates stream flow control and calls the data provider callback (server_read_callback), which reads from the freed buffer via memmove(). The UAF read is confirmed by AddressSanitizer and reliably crashes ASAN-instrumented builds (~40% per round). Against production BIND builds using jemalloc, the freed memory remains mapped and the read succeeds silently — the server does not crash. Information disclosure via the HTTP/2 DATA stream was not confirmed: although server_read_callback reads freed heap bytes, nghttp2 discards the result because the stream’s data provider had already signaled EOF; no extra bytes are transmitted to the attacker. The practical impact is therefore denial of service against hardened builds, and a latent memory safety violation in production that could become exploitable if nghttp2’s internal handling changes. ISC addressed this vulnerability in BIND 9.20.23 and 9.21.22. ...

1. Overview A use-after-free vulnerability exists in the Linux kernel’s BPF netfilter link implementation. The bpf_nf_link_lops operations structure uses synchronous deallocation (.dealloc) instead of RCU-deferred freeing (.dealloc_deferred), allowing a use-after-free when concurrent hook enumeration via nfnetlink races with BPF link destruction. The UAF on the kmalloc-192 slab cache is exploitable for local privilege escalation through heap spray and function pointer hijacking. The Linux kernel community addressed this vulnerability in kernel version 7.0-rc5. ...