UBUNTU-CVE-2026-10645 (CVE-2026-10645)
Vulnerability from osv_ubuntu – Published: 2026-06-23 01:16 – Updated: 2026-07-15 17:48 – Source website
VLAI
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 > 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.
Severity
4.9 (Medium)
5.5 (Medium)
N/A (UNKNOWN)
References
{
"affected": [
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libzephyr4",
"binary_version": "3.1.2-1build1"
},
{
"binary_name": "libzephyr4-krb5",
"binary_version": "3.1.2-1build1"
},
{
"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"
}
]
},
"package": {
"ecosystem": "Ubuntu:16.04:LTS",
"name": "zephyr",
"purl": "pkg:deb/ubuntu/zephyr@3.1.2-1build1?arch=source\u0026distro=xenial"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.1.2-1",
"3.1.2-1build1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libzephyr4",
"binary_version": "3.1.2-1build2"
},
{
"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"
}
]
},
"package": {
"ecosystem": "Ubuntu:18.04:LTS",
"name": "zephyr",
"purl": "pkg:deb/ubuntu/zephyr@3.1.2-1build2?arch=source\u0026distro=bionic"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.1.2-1build1",
"3.1.2-1build2"
]
},
{
"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_name": "zephyr-server-krb5",
"binary_version": "3.1.2-1build3"
}
]
},
"package": {
"ecosystem": "Ubuntu:20.04:LTS",
"name": "zephyr",
"purl": "pkg:deb/ubuntu/zephyr@3.1.2-1build3?arch=source\u0026distro=focal"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"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_name": "zephyr-server-krb5",
"binary_version": "3.1.2-1build3"
}
]
},
"package": {
"ecosystem": "Ubuntu:22.04:LTS",
"name": "zephyr",
"purl": "pkg:deb/ubuntu/zephyr@3.1.2-1build3?arch=source\u0026distro=jammy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.1.2-1build3"
]
},
{
"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_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",
"binary_version": "3.1.2-1.1build1"
}
]
},
"package": {
"ecosystem": "Ubuntu:24.04:LTS",
"name": "zephyr",
"purl": "pkg:deb/ubuntu/zephyr@3.1.2-1.1build1?arch=source\u0026distro=noble"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"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_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",
"binary_version": "3.1.2-1.1build1"
}
]
},
"package": {
"ecosystem": "Ubuntu:25.10",
"name": "zephyr",
"purl": "pkg:deb/ubuntu/zephyr@3.1.2-1.1build1?arch=source\u0026distro=questing"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.1.2-1.1build1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libzephyr4",
"binary_version": "3.1.2-4"
},
{
"binary_name": "libzephyr4-krb5",
"binary_version": "3.1.2-4"
},
{
"binary_name": "zephyr-clients",
"binary_version": "3.1.2-4"
},
{
"binary_name": "zephyr-server",
"binary_version": "3.1.2-4"
},
{
"binary_name": "zephyr-server-krb5",
"binary_version": "3.1.2-4"
}
]
},
"package": {
"ecosystem": "Ubuntu:26.04:LTS",
"name": "zephyr",
"purl": "pkg:deb/ubuntu/zephyr@3.1.2-4?arch=source\u0026distro=resolute"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.1.2-1.1build1",
"3.1.2-4"
]
}
],
"aliases": [],
"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\u0027d 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\u0027 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\u0027s 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.",
"id": "UBUNTU-CVE-2026-10645",
"modified": "2026-07-15T17:48:10Z",
"published": "2026-06-23T01:16:00Z",
"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"
}
],
"related": [],
"schema_version": "1.7.0",
"severity": [
{
"score": "CVSS:3.1/AV:P/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
],
"upstream": [
"CVE-2026-10645"
]
}
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Sightings
| Author | Source | Type | Date | Other |
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vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
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Browse all ATT&CK techniques and the vulnerabilities related to each.
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