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vuln-cve/data/2026/12xxx/CVE-2026-12235.json
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{
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"cveMetadata": {
"cveId": "CVE-2026-12235",
"assignerOrgId": "e2e69745-5e70-4e92-8431-deb5529a81ad",
"state": "PUBLISHED",
"assignerShortName": "zephyr",
"dateReserved": "2026-06-15T01:56:05.689Z",
"datePublished": "2026-08-12T04:55:15.620Z",
"dateUpdated": "2026-11-04T04:59:20.913Z"
},
"containers": {
"cna": {
"providerMetadata": {
"orgId": "e2e69745-5e70-4e92-8431-deb5529a81ad",
"shortName": "zephyr",
"dateUpdated": "2026-11-04T04:59:20.913Z"
},
"title": "Out-of-bounds write in Xtensa llext PLT relocation from malformed ELF (CWE-787)",
"descriptions": [
{
"lang": "en",
"value": "The Linkable Loadable Extensions (llext) subsystem mis-handles PLT/RELA relocation entries when linking a relocatable (partially-linked) ELF extension. In llext_link_plt() (subsys/llext/llext_link.c), the relocatable branch (tgt != NULL, the path used for Xtensa relocatable objects) computed the patch address as ext->mem[LLEXT_MEM_TEXT] - text.sh_offset + rela.r_offset + tgt->sh_offset and then performed the relocation write there without validating rela.r_offset. Its sibling shared/dynamic branch already rejected out-of-range offsets via llext_file_offset().\n\nrela.r_offset is read directly from the ELF's RELA table, so a crafted entry with an offset larger than the target section makes the write land arbitrarily far outside the extension's text buffer. The result is an attacker-influenced out-of-bounds write (the location via r_offset, the written value being the resolved symbol address) performed in supervisor context at link time, before any extension code runs.\n\nThe path is reached from llext_load() whenever an application loads an attacker-influenced ELF extension on Xtensa with writable storage; llext is documented to accept extensions of untrusted origin. Impact is supervisor-context memory corruption (integrity and availability loss, and a sandbox-boundary escape for user-mode extensions). Exploitation is gated by the Xtensa relocatable PLT path and writable storage, and turning the out-of-range write into a useful primitive is non-trivial.\n\nThe fix adds a bound check rejecting any RELA entry whose r_offset >= tgt->sh_size, mirroring the existing validation in the shared branch."
}
],
"affected": [
{
"vendor": "zephyrproject",
"product": "zephyr",
"collectionURL": "https://github.com/zephyrproject-rtos/zephyr",
"packageName": "zephyr",
"defaultStatus": "unaffected",
"programFiles": [
"subsys/llext/llext_link.c"
],
"versions": [
{
"version": "3.7.0",
"status": "affected",
"versionType": "semver",
"lessThan": "4.3.2"
},
{
"version": "4.4.0",
"status": "affected",
"versionType": "semver",
"lessThan": "4.4.2"
}
]
}
],
"references": [
{
"url": "https://github.com/zephyrproject-rtos/zephyr/commit/106540afbd22087ad40b90f53fb22657754a719e",
"name": "Fix commit",
"tags": [
"patch"
]
},
{
"url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-xv9q-6mrf-8j49",
"name": "GHSA-xv9q-6mrf-8j49"
}
],
"metrics": [
{
"format": "CVSS",
"cvssV3_1": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:H",
"baseScore": 6.3,
"baseSeverity": "MEDIUM"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"lang": "en",
"description": "bounds",
"cweId": "CWE-787",
"type": "CWE"
}
]
}
],
"x_generator": {
"engine": "cvelib 1.8.0"
}
},
"adp": [
{
"references": [
{
"url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-xv9q-6mrf-8j49",
"tags": [
"exploit"
]
}
],
"metrics": [
{
"other": {
"type": "ssvc",
"content": {
"timestamp": "2026-08-12T12:34:31.991332Z",
"id": "CVE-2026-12235",
"options": [
{
"Exploitation": "poc"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
}
],
"title": "CISA ADP Vulnrichment",
"providerMetadata": {
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP",
"dateUpdated": "2026-08-12T12:34:55.518Z"
}
}
]
}
}