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Vulnerability · Published Jul 24, 2026 · Assigned by Linux

CVE-2026-64253kernel/fork: clear PF_BLOCK_TS in copy_process()

Medium 5.5

In plain English

A medium-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 1% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)5.5Medium
Exploit odds (30 days)0.1%top 98.5% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: kernel/fork: clear PF_BLOCK_TS in copy_process() PF_BLOCK_TS is only set in blk_time_get_ns() when current->plug is non-NULL, and blk_finish_plug() clears it via __blk_flush_plug() before NULLing the plug pointer. copy_process() breaks the invariant by inheriting PF_BLOCK_TS from the parent while resetting the child's plug to NULL. Clear PF_BLOCK_TS alongside that assignment so callers can rely on "PF_BLOCK_TS set implies current->plug != NULL" and dereference current->plug unguarded.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:13linux6.12.95-1DEBIAN-CVE-2026-64253
Debian:14linux7.1.3-1DEBIAN-CVE-2026-64253
Ubuntu:26.04:LTSlinux7.0.0-31.31UBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-64253
Ubuntu:26.04:LTSlinux-aws7.0.0-1012.12UBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-aws-7.07.0.0-1012.12~24.04.1UBUNTU-CVE-2026-64253
Ubuntu:26.04:LTSlinux-azure7.0.0-1014.14UBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-azure-7.07.0.0-1014.14~24.04.1UBUNTU-CVE-2026-64253
Ubuntu:26.04:LTSlinux-azure-fde7.0.0-1013.13UBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-azure-fde-7.07.0.0-1013.13~24.04.1UBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-64253
Ubuntu:26.04:LTSlinux-gcp7.0.0-1011.11UBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-gcp-7.07.0.0-1011.11~24.04.1UBUNTU-CVE-2026-64253
Ubuntu:26.04:LTSlinux-gke7.0.0-1006.7UBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-hwe-6.17no fix listedUBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-hwe-7.07.0.0-31.31~24.04.1UBUNTU-CVE-2026-64253
Ubuntu:26.04:LTSlinux-ibm7.0.0-1013.13UBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-64253
Ubuntu:26.04:LTSlinux-nvidia7.0.0-1018.18UBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-nvidia-7.07.0.0-1018.18~24.04.1UBUNTU-CVE-2026-64253
Ubuntu:26.04:LTSlinux-nvidia-bos7.0.0-2018.18UBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-oem-6.17no fix listedUBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-64253
Ubuntu:26.04:LTSlinux-oem-7.07.0.0-1013.13UBUNTU-CVE-2026-64253
Ubuntu:26.04:LTSlinux-oracle7.0.0-1011.11UBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-oracle-7.07.0.0-1011.11~24.04.1UBUNTU-CVE-2026-64253
Ubuntu:26.04:LTSlinux-raspi7.0.0-1019.19UBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-64253
Ubuntu:26.04:LTSlinux-realtime7.0.0-31.31.1UBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-64253
Ubuntu:26.04:LTSlinux-riscv7.0.0-31.31.1UBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-64253
Ubuntu:24.04:LTSlinux-riscv-7.07.0.0-31.31.1~24.04.1UBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-64253
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-64253

Affected products (as reported)

VendorProductVersions
Linux Linux 06b23f92af87a84d70881b2ecaa72e00f7838264 – before ee0801aceabdf583392477baf69a290b09448b8f06b23f92af87a84d70881b2ecaa72e00f7838264 – before 99e6c712cc300883b8cbf03347d5359ec1a4d6dd06b23f92af87a84d70881b2ecaa72e00f7838264 – before 77bba61a20f1b3d206f4f90e10a7bb3cd90b961906b23f92af87a84d70881b2ecaa72e00f7838264 – before fd38b75c4b43295b10d69772a46d1c74dbd6fc81
Linux Linux 6.9

References