{"affected":[{"defaultStatus":"unaffected","ecosystem":"https://github.com/zephyrproject-rtos/zephyr","packageName":"zephyr","product":"zephyr","source":"CNA: zephyr","vendor":"zephyrproject","versions":[{"lessThan":"4.6.0","status":"affected","version":"3.5.0","versionType":"semver"}]}],"cpeConfigurations":[{"negate":false,"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:zephyrproject:zephyr:*:*:*:*:*:*:*:*","versionEndIncluding":"4.4.1","vulnerable":true}],"negate":false,"operator":"OR"}],"operator":"OR"}],"cveId":"CVE-2026-10645","cwes":["CWE-125"],"description":"The Zephyr ext2 filesystem driver (subsys/fs/ext2) trusted the on-disk directory entry fields de_rec_len and de_name_len when walking a directory block. ext2_fetch_direntry() guarded only with de_name_len > EXT2_MAX_FILE_NAME, but de_name_len is a uint8_t and EXT2_MAX_FILE_NAME is 255, so the check is always false; the function then memcpy'd up to 255 name bytes and the lookup/readdir paths advanced traversal by an unvalidated de_rec_len. Each directory block is read into a block_size-sized slab buffer, and block_off can be driven near the block end by preceding entries' rec_len, so the 8-byte header read and the subsequent name memcpy can read up to ~263 bytes past the end of the block buffer into adjacent heap/slab memory. On the readdir path those bytes are returned to the caller in fs_dirent.name, leaking adjacent kernel heap memory; a de_rec_len of 0 also causes a zero-progress infinite loop (denial of service), and the unlink path's memmove(de, next, next_reclen) over unvalidated records is an additional OOB read/write source. The defect is reached by any path-based operation (open, stat, unlink, rename, mkdir) or directory listing on a mounted ext2 volume, so a crafted or corrupted ext2 image on attacker-supplied storage (SD card, USB mass storage, or otherwise mounted image) triggers it. Affected: Zephyr ext2 from its introduction in v3.5.0 through v4.4.0. The fix validates rec_len and name_len in the parser and rejects entries whose header does not fit the remaining block or whose rec_len crosses the block boundary in every traversal caller.","epss":{"date":"2026-11-03","percentile":0.04959,"score":0.00158},"exploits":[{"kind":"exploit","source":"vulnerabilities@zephyrproject.org","url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-hwrh-9h3x-vccm"}],"kev":null,"metrics":[{"score":4.9,"severity":"medium","source":"CNA: zephyr","vector":"CVSS:3.1/AV:P/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H","version":"3.1"},{"score":5.5,"severity":"medium","source":"NVD: nvd@nist.gov","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","version":"3.1"},{"score":4.9,"severity":"medium","source":"NVD: vulnerabilities@zephyrproject.org","vector":"CVSS:3.1/AV:P/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H","version":"3.1"}],"modifiedAt":1793769503483,"publishedAt":1782172091747,"references":[{"source":"CNA: zephyr","tags":["patch"],"url":"https://github.com/zephyrproject-rtos/zephyr/commit/7cdb534a3c3daeaec18f656953857dcafa33a2bf"},{"source":"CNA: zephyr","tags":[],"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-hwrh-9h3x-vccm"},{"source":"vulnerabilities@zephyrproject.org","tags":[],"url":"https://github.com/zephyrproject-rtos/zephyr/commit/7cdb534a3c3daeaec18f656953857dcafa33a2bf"},{"source":"vulnerabilities@zephyrproject.org","tags":["Exploit","Patch","Vendor Advisory"],"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-hwrh-9h3x-vccm"}],"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/7cdb534a3c3daeaec18f656953857dcafa33a2bf"},{"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-hwrh-9h3x-vccm"}],"revision":"4046756499feaf662d33758a4d454b2de78ba7a439fe018f29f8cbe988cee2b9","sources":[{"modifiedAt":1793768298458,"name":"CNA: zephyr","retrievedAt":1793768915232,"url":"https://www.cve.org/CVERecord?id=CVE-2026-10645"},{"modifiedAt":1793769503483,"name":"NVD","retrievedAt":1793772948355,"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-10645"},{"modifiedAt":null,"name":"FIRST EPSS","retrievedAt":1793768927297,"url":"https://api.first.org/data/v1/epss?cve=CVE-2026-10645"}],"ssvc":{"assessedAt":1782217106712,"automatable":"no","exploitation":"none","source":"ADP: CISA-ADP","technicalImpact":"partial"},"status":"published","title":"Out-of-bounds read in Zephyr ext2 directory entry traversal from a crafted filesystem image","updatedAt":1793772948355}