128 lines
6.4 KiB
JSON
128 lines
6.4 KiB
JSON
{
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"dataType": "CVE_RECORD",
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"dataVersion": "5.2",
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"cveMetadata": {
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"cveId": "CVE-2026-13478",
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"assignerOrgId": "e2e69745-5e70-4e92-8431-deb5529a81ad",
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"state": "PUBLISHED",
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"assignerShortName": "zephyr",
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"dateReserved": "2026-06-27T13:33:54.323Z",
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"datePublished": "2026-08-25T16:05:39.217Z",
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"dateUpdated": "2026-11-04T04:59:57.906Z"
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},
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"containers": {
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"cna": {
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"providerMetadata": {
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"orgId": "e2e69745-5e70-4e92-8431-deb5529a81ad",
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"shortName": "zephyr",
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"dateUpdated": "2026-11-04T04:59:57.906Z"
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},
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"title": "Out-of-bounds read in Zephyr ext2 block-bitmap validation from a crafted s_blocks_count",
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"descriptions": [
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{
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"lang": "en",
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"value": "The Zephyr ext2 filesystem driver validates the on-disk block bitmap in ext2_init_fs() (subsys/fs/ext2/ext2_impl.c) by passing fs_blocks = s_blocks_count - s_first_data_block to ext2_bitmap_count_set(). That helper (subsys/fs/ext2/ext2_bitmap.c) treats its argument as a number of bits and reads one bitmap byte per eight bits, but the bitmap buffer (BGROUP_BLOCK_BITMAP) is a single fetched block of only fs->block_size bytes (capacity fs->block_size * 8 bits). s_blocks_count and s_first_data_block are taken verbatim from the superblock and were never bounded against this single-group capacity; ext2_verify_disk_superblock() checks the magic, revision, and block-size shift but not the block count.\n\nA crafted ext2 image with an oversized s_blocks_count (up to ~4 billion, against a maximum 4096-byte block / 32768-bit bitmap) makes ext2_bitmap_count_set() scan roughly 512 MB of memory past the bitmap block — a large out-of-bounds read of the static block slab and adjacent memory.\n\nThe defect is reached during mount: ext2_init_fs() is invoked from ext2_mount() (subsys/fs/ext2/ext2_ops.c), the registered .mount operation. Any path that mounts an attacker-supplied ext2 image (removable media, a disk/flash partition, or a downloaded image) triggers it. The kernel-privileged parser operates on attacker-controlled data, so the bug is exploitable wherever untrusted ext2 media can be mounted.\n\nImpact is an out-of-bounds read only: the resulting bit count is compared internally and the mount is rejected, so no attacker-controlled bytes are returned (not a useful information leak). The ~512 MB over-read will almost certainly cross an unmapped or MPU-protected boundary and fault, crashing the system — a denial of service triggered by mounting a single malformed image. The fix rejects any image whose fs_blocks exceeds fs->block_size * 8 before the scan."
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}
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],
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"affected": [
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{
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"vendor": "zephyrproject",
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"product": "zephyr",
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"collectionURL": "https://github.com/zephyrproject-rtos/zephyr",
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"packageName": "zephyr",
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"defaultStatus": "unaffected",
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"programFiles": [
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"subsys/fs/ext2/ext2_impl.c"
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],
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"versions": [
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{
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"version": "3.5.0",
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"status": "affected",
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"versionType": "semver",
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"lessThan": "4.3.2"
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},
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{
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"version": "4.4.0",
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"status": "affected",
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"versionType": "semver",
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"lessThan": "4.4.2"
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}
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]
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}
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],
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"references": [
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{
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"url": "https://github.com/zephyrproject-rtos/zephyr/commit/9c0f869da07009d9d4bca7a99e995f9b8cea7da2",
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"name": "Fix commit",
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"tags": [
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"patch"
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]
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},
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{
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"url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-gj29-7f7m-4c29",
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"name": "GHSA-gj29-7f7m-4c29"
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}
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],
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"metrics": [
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{
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"format": "CVSS",
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"cvssV3_1": {
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"version": "3.1",
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"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
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"baseScore": 5.5,
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"baseSeverity": "MEDIUM"
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}
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}
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],
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"problemTypes": [
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{
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"descriptions": [
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{
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"lang": "en",
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"description": "bounds",
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"cweId": "CWE-125",
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"type": "CWE"
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}
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]
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}
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],
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"x_generator": {
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"engine": "cvelib 1.8.0"
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}
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},
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"adp": [
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{
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"metrics": [
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{
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"other": {
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"type": "ssvc",
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"content": {
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"timestamp": "2026-08-25T19:39:34.544787Z",
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"id": "CVE-2026-13478",
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"options": [
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{
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"Exploitation": "none"
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},
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{
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"Automatable": "no"
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},
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{
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"Technical Impact": "partial"
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}
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],
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"role": "CISA Coordinator",
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"version": "2.0.3"
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}
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}
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}
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],
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"title": "CISA ADP Vulnrichment",
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"providerMetadata": {
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"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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"shortName": "CISA-ADP",
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"dateUpdated": "2026-08-25T19:39:52.183Z"
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}
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}
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]
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}
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} |