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Vulnerability · Published Sep 11, 2026 · Assigned by Linux

CVE-2026-89639cifs: use cifs_invalidate_cache() in cifs_do_truncate() for O_TRUNC

High 7.1

In plain English

A high-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 2% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.1High
Exploit odds (30 days)0.1%top 97.8% 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: cifs: use cifs_invalidate_cache() in cifs_do_truncate() for O_TRUNC cifs_do_truncate() is invoked from cifs_open() without i_rwsem, so it cannot use cifs_resize_file_locked() to perform a proper fscache cookie resize. Instead, add cifs_invalidate_cache() after cifs_setsize(). cifs_invalidate_cache() calls fscache_invalidate(), which works without holding i_rwsem: it unconditionally increments inval_counter and sets FSCACHE_COOKIE_NO_DATA_TO_READ, ensuring that stale cached data is not served once the cookie is later activated by fscache_use_cookie(). Truncation to zero leaves no valid cached data, making invalidation the correct semantic here.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:13linuxno fix listedDEBIAN-CVE-2026-89639
Debian:14linux7.2.6-1DEBIAN-CVE-2026-89639
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-azure-fde-6.17no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-89639
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-89639
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-89639

Affected products (as reported)

VendorProductVersions
Linux Linux efbcecdecefc26fa062c0e8210533ccad7d6bd4a – before 8b9b10fe5b8b492b27b9f4546742ea541a650213fa724e235cfdb0fb0bb427d0f9dfe864ae27403e – before 81fc3868a7f726980ff845c1d0d271051e5f0f45fa724e235cfdb0fb0bb427d0f9dfe864ae27403e – before 364b183230586a62660a7280c1eb20138338eeb56838bcac954487cc0a3c8a4ee1b3a3a30e244dc975640976cf474eb41682a13f2dbe9534ac26ca503513f3931c579ba2a715784c6dedc59e0d9282ee6.18.44 – before 6.18.506.12.105 – before 6.13
Linux Linux 7.2

References