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Unterminated URI buffer causes out-of-bounds read in LwM2M firmware pull (Package URI)

Type: advisorySource: Official CVE List1 source record

subsys/net/lib/lwm2m/lwm2m_pull_context.c copied the firmware-update Package URI into a fixed static buffer (context.uri, size CONFIG_LWM2M_SWMGMT_PACKAGE_URI_LEN, default 128) with memcpy(context.uri, uri, LWM2M_PACKAGE_URI_LEN), copying exactly the destination size with no length validation. The Firmware-Update object stores the server-supplied Package URI (/5/0/1) in a 255-byte buffer, so a LwM2M management server (or an on-path attacker on a session lacking strong DTLS) can WRITE a URI of 128-254 characters; only the first 128 bytes are then copied into context.uri with no NUL terminator. That buffer is subsequently consumed as a C string by http_parser_parse_url(context.uri, strlen(context.uri), ...), strlen-based CoAP URI-path/PROXY-URI option appends, and lwm2m_parse_peerinfo(), causing an out-of-bounds read of adjacent static memory. The over-read bytes are appended to outbound CoAP requests (information disclosure of adjacent device memory to the server/proxy) and can crash the device (denial of service). The vulnerable copy was introduced by the pull-context refactor (first released in v3.0.0) and is present through v4.4.0; the default-on CONFIG_LWM2M_FIRMWARE_UPDATE_PULL_SUPPORT path is affected. The fix adds a strlen(uri) >= sizeof(context.uri) check returning -ENOMEM and switches to strcpy(), guaranteeing a bounded, NUL-terminated buffer.

Announced Group revision 1
Original source ↗

CVE-2026-10672

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-10672

zephyr

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "vendor": "zephyrproject",
    "product": "zephyr",
    "versions": [
      {
        "status": "affected",
        "version": "3.0.0",
        "lessThan": "4.3.1",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "4.4.0",
        "lessThan": "4.4.1",
        "versionType": "semver"
      }
    ],
    "packageName": "zephyr",
    "programFiles": [
      "subsys/net/lib/lwm2m/lwm2m_pull_context.c"
    ],
    "collectionURL": "https://github.com/zephyrproject-rtos/zephyr",
    "defaultStatus": "unaffected"
  }
]
Related CVEs
CVE-2026-10672

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#32256 · Revision 1
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Publisher date
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