{"id":"UBUNTU-CVE-2026-10645","details":"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 \u003e 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.","modified":"2026-07-15T19:45:57.519773620Z","published":"2026-06-23T01:16:00Z","upstream":["CVE-2026-10645"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-10645"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-10645"},{"type":"REPORT","url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-hwrh-9h3x-vccm"}],"affected":[{"package":{"name":"zephyr","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/zephyr?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.1.2-1","3.1.2-1build1"],"ecosystem_specific":{"binaries":[{"binary_version":"3.1.2-1build1","binary_name":"libzephyr4"},{"binary_version":"3.1.2-1build1","binary_name":"libzephyr4-krb5"},{"binary_name":"zephyr-clients","binary_version":"3.1.2-1build1"},{"binary_name":"zephyr-server","binary_version":"3.1.2-1build1"},{"binary_name":"zephyr-server-krb5","binary_version":"3.1.2-1build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-10645.json"}},{"package":{"name":"zephyr","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/zephyr?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.1.2-1build1","3.1.2-1build2"],"ecosystem_specific":{"binaries":[{"binary_version":"3.1.2-1build2","binary_name":"libzephyr4"},{"binary_name":"libzephyr4-krb5","binary_version":"3.1.2-1build2"},{"binary_name":"zephyr-clients","binary_version":"3.1.2-1build2"},{"binary_name":"zephyr-server","binary_version":"3.1.2-1build2"},{"binary_name":"zephyr-server-krb5","binary_version":"3.1.2-1build2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-10645.json"}},{"package":{"name":"zephyr","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/zephyr?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.1.2-1build3"],"ecosystem_specific":{"binaries":[{"binary_name":"libzephyr4","binary_version":"3.1.2-1build3"},{"binary_version":"3.1.2-1build3","binary_name":"libzephyr4-krb5"},{"binary_name":"zephyr-clients","binary_version":"3.1.2-1build3"},{"binary_name":"zephyr-server","binary_version":"3.1.2-1build3"},{"binary_name":"zephyr-server-krb5","binary_version":"3.1.2-1build3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-10645.json"}},{"package":{"name":"zephyr","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/zephyr?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.1.2-1build3"],"ecosystem_specific":{"binaries":[{"binary_name":"libzephyr4","binary_version":"3.1.2-1build3"},{"binary_name":"libzephyr4-krb5","binary_version":"3.1.2-1build3"},{"binary_name":"zephyr-clients","binary_version":"3.1.2-1build3"},{"binary_name":"zephyr-server","binary_version":"3.1.2-1build3"},{"binary_version":"3.1.2-1build3","binary_name":"zephyr-server-krb5"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-10645.json"}},{"package":{"name":"zephyr","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/zephyr?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.1.2-1.1","3.1.2-1.1build1"],"ecosystem_specific":{"binaries":[{"binary_name":"libzephyr4","binary_version":"3.1.2-1.1build1"},{"binary_name":"libzephyr4-krb5","binary_version":"3.1.2-1.1build1"},{"binary_version":"3.1.2-1.1build1","binary_name":"zephyr-clients"},{"binary_version":"3.1.2-1.1build1","binary_name":"zephyr-server"},{"binary_version":"3.1.2-1.1build1","binary_name":"zephyr-server-krb5"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-10645.json"}},{"package":{"name":"zephyr","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/zephyr?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.1.2-1.1build1"],"ecosystem_specific":{"binaries":[{"binary_name":"libzephyr4","binary_version":"3.1.2-1.1build1"},{"binary_name":"libzephyr4-krb5","binary_version":"3.1.2-1.1build1"},{"binary_version":"3.1.2-1.1build1","binary_name":"zephyr-clients"},{"binary_version":"3.1.2-1.1build1","binary_name":"zephyr-server"},{"binary_name":"zephyr-server-krb5","binary_version":"3.1.2-1.1build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-10645.json"}},{"package":{"name":"zephyr","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/zephyr?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.1.2-1.1build1","3.1.2-4"],"ecosystem_specific":{"binaries":[{"binary_name":"libzep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