UBUNTU-CVE-2026-10645

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Source
https://ubuntu.com/security/CVE-2026-10645
Import Source
https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-10645.json
JSON Data
https://api.osv.dev/v1/vulns/UBUNTU-CVE-2026-10645
Upstream
Published
2026-06-23T01:16:00Z
Modified
2026-07-15T19:45:57Z
Severity
  • 4.9 (Medium) CVSS_V3 - CVSS:3.1/AV:P/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H CVSS Calculator
  • 5.5 (Medium) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H CVSS Calculator
  • Ubuntu - medium
Summary
[none]
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.

References

Affected packages

Ubuntu:16.04:LTS
zephyr

Package

Name
zephyr
Purl
pkg:deb/ubuntu/zephyr?arch=source&distro=xenial

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

3.*
3.1.2-1
3.1.2-1build1

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"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-10645.json"
Ubuntu:18.04:LTS
zephyr

Package

Name
zephyr
Purl
pkg:deb/ubuntu/zephyr?arch=source&distro=bionic

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

3.*
3.1.2-1build1
3.1.2-1build2

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"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-10645.json"
Ubuntu:20.04:LTS
zephyr

Package

Name
zephyr
Purl
pkg:deb/ubuntu/zephyr?arch=source&distro=focal

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

3.*
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"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-10645.json"
Ubuntu:22.04:LTS
zephyr

Package

Name
zephyr
Purl
pkg:deb/ubuntu/zephyr?arch=source&distro=jammy

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

3.*
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"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-10645.json"
Ubuntu:24.04:LTS
zephyr

Package

Name
zephyr
Purl
pkg:deb/ubuntu/zephyr?arch=source&distro=noble

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

3.*
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"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-10645.json"
Ubuntu:25.10
zephyr

Package

Name
zephyr
Purl
pkg:deb/ubuntu/zephyr?arch=source&distro=questing

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

3.*
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"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-10645.json"
Ubuntu:26.04:LTS
zephyr

Package

Name
zephyr
Purl
pkg:deb/ubuntu/zephyr?arch=source&distro=resolute

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected

Affected versions

3.*
3.1.2-1.1build1
3.1.2-4

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"
        }
    ]
}

Database specific

source 
"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-10645.json"