{"affected":[{"defaultStatus":"unaffected","ecosystem":"https://github.com/zephyrproject-rtos/zephyr","packageName":"zephyr","product":"zephyr","source":"CNA: zephyr","vendor":"zephyrproject","versions":[{"lessThan":"4.3.2","status":"affected","version":"3.5.0","versionType":"semver"},{"lessThan":"4.4.2","status":"affected","version":"4.4.0","versionType":"semver"}]}],"cpeConfigurations":[{"negate":false,"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:zephyrproject:zephyr:*:*:*:*:*:*:*:*","versionEndExcluding":"4.5.0","versionStartIncluding":"3.5.0","vulnerable":true}],"negate":false,"operator":"OR"}],"operator":"OR"}],"cveId":"CVE-2026-7007","cwes":["CWE-369"],"description":"The Zephyr ext2 file system validates the on-disk superblock in ext2_verify_disk_superblock() (subsys/fs/ext2/ext2_impl.c) before completing a mount. The validator checked the magic number, block size, revision and feature flags, but did not verify that the on-disk fields s_blocks_per_group and s_inodes_per_group are non-zero. Both fields are read directly from the image and are later used as divisors during mount-time initialization.\n\nDuring mount, get_ngroups() divides and modulos s_blocks_count by s_blocks_per_group (reached via ext2_fetch_block_group() from ext2_init_fs()), and get_itable_entry() divides (ino - 1) by s_inodes_per_group when fetching the root inode (both in subsys/fs/ext2/ext2_diskops.c). A superblock with either field set to zero therefore causes an integer division by zero during the mount sequence.\n\nAn attacker who can present a crafted ext2 image to a device that mounts ext2 — removable media such as an SD card or a USB mass-storage device — can trigger this. On ARMv7-M / ARMv8-M-mainline Cortex-M targets, divide-by-zero trapping is enabled (SCB_CCR_DIV_0_TRP), so the division raises a UsageFault that Zephyr treats as a fatal error, producing a denial of service. The impact is limited to availability; the malformed value is consumed only as a divisor.\n\nThe fix rejects a zero s_blocks_per_group or s_inodes_per_group in the superblock validator, returning -EINVAL so the mount fails before any block-group or inode I/O occurs.","epss":{"date":"2026-11-03","percentile":0.15608,"score":0.00243},"exploits":[{"kind":"exploit","source":"vulnerabilities@zephyrproject.org","url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-wrf2-79mm-cvw5"}],"kev":null,"metrics":[{"score":4.6,"severity":"medium","source":"CNA: zephyr","vector":"CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},{"score":4.6,"severity":"medium","source":"NVD: vulnerabilities@zephyrproject.org","vector":"CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}],"modifiedAt":1793769543217,"publishedAt":1784900904831,"references":[{"source":"CNA: zephyr","tags":["patch"],"url":"https://github.com/zephyrproject-rtos/zephyr/commit/babc0900ed40e6c023ccc26aa1a321f9388b66af"},{"source":"CNA: zephyr","tags":[],"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-wrf2-79mm-cvw5"},{"source":"vulnerabilities@zephyrproject.org","tags":["Patch"],"url":"https://github.com/zephyrproject-rtos/zephyr/commit/babc0900ed40e6c023ccc26aa1a321f9388b66af"},{"source":"vulnerabilities@zephyrproject.org","tags":["Exploit","Patch","Vendor Advisory"],"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-wrf2-79mm-cvw5"}],"remediation":[{"kind":"fix","source":"CNA: zephyr","text":"The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.","url":"https://github.com/zephyrproject-rtos/zephyr/commit/babc0900ed40e6c023ccc26aa1a321f9388b66af"},{"kind":"fix","source":"vulnerabilities@zephyrproject.org","text":"The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.","url":"https://github.com/zephyrproject-rtos/zephyr/commit/babc0900ed40e6c023ccc26aa1a321f9388b66af"},{"kind":"fix","source":"vulnerabilities@zephyrproject.org","text":"The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.","url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-wrf2-79mm-cvw5"}],"revision":"187771fcb03ae4725db9bc3e31f9268c98e42d9997e56ab3b27a90c46480afe2","sources":[{"modifiedAt":1793768339468,"name":"CNA: zephyr","retrievedAt":1793769125571,"url":"https://www.cve.org/CVERecord?id=CVE-2026-7007"},{"modifiedAt":1793769543217,"name":"NVD","retrievedAt":1793772951380,"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-7007"},{"modifiedAt":null,"name":"FIRST EPSS","retrievedAt":1793769137241,"url":"https://api.first.org/data/v1/epss?cve=CVE-2026-7007"}],"ssvc":{"assessedAt":1784905406497,"automatable":"no","exploitation":"none","source":"ADP: CISA-ADP","technicalImpact":"partial"},"status":"published","title":"Division by zero in Zephyr ext2 superblock parsing allows DoS via crafted filesystem image","updatedAt":1793772951380}