QEMU cursor CVE and PostgreSQL standby, WAL, and partition fixes

Security work on QEMU's virtio-gpu cursor path leads the day, with several PostgreSQL correctness bugs under active patch review. A large Arm Realm RFC also advances confidential-guest support in QEMU.

QEMU virtio-gpu rejects non-32bpp cursor resources

A four-patch series on qemu-devel adds 32 bits-per-pixel checks for cursor resources across virtio-gpu backends. The change addresses CVE-2026-122027, which allowed out-of-bounds reads when a guest supplied a cursor resource that was not 32bpp. Operators of QEMU guests that expose virtio-gpu should track the series, since a malformed cursor can read past the resource buffer.

Offline checksum changes can leave standbys in a bad state

A pgsql-hackers thread reports that changing data checksums offline can leave PostgreSQL standbys with a mismatched or unreadable checksum state. The discussion, spanning 45 messages, is still working through patches. Standby operators who enable or disable checksums outside a running primary should treat the current behavior as unsafe until a fix lands.

Parallel workers double-count WAL statistics

A proposed patch stops parallel workers from being counted twice in cumulative WAL statistics. The bug has affected pg_stat_wal and EXPLAIN since PostgreSQL 14. Anyone using those views to size WAL or to explain write amplification has been reading inflated numbers.

Interrupted concurrent partition detach can crash

Patches and review continue for crashes and publication inconsistencies after DETACH PARTITION CONCURRENTLY is interrupted before it finishes. The failures are described as a PostgreSQL 19 regression. Sites that detach partitions concurrently, or that publish those tables, can hit a crash or an inconsistent publication state if the detach does not complete.

SGX EPC device lacks its memory backend type

A bug report notes that qemu-system-x86_64 advertises sgx-epc but does not provide the memory-backend-epc type the device needs. The thread turned into a discussion of conditional type registration and QOM object lifecycles, and a patch series has been posted. SGX users cannot currently wire an EPC backend the way the device model expects.

Autovacuum may refresh database frozen IDs more often

A patch proposes refreshing datfrozenxid periodically inside autovacuum workers. The goal is to stop database horizons from going stale on databases with hundreds of thousands of tables. Large catalogs that rely on autovacuum to advance the frozen-XID horizon are the audience for the change.

Interruptible background workers fail to restart after database DDL

A bug report on unreleased PostgreSQL 19 says workers marked BGWORKER_INTERRUPTIBLE are never restarted after DROP, ALTER, or CREATE DATABASE. A patch is proposed to restore the previous restart behavior. Extensions that depend on those workers surviving database DDL will stay down until the termination logic is fixed.

RFC adds Arm Realm support to QEMU

An RFC v4 series of 24 patches adds Arm Realm Management Extension confidential guest support to QEMU's virtual machine monitor. The work integrates with KVM guest-memfd and the Realm Management Monitor. It is still an RFC, but it is the concrete path for running Arm confidential guests under QEMU.