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CVE-2026-13479— Out-of-bounds read in LoRaWAN clock-sync AppTimeAns downlink handler

Quick assessment

Affected
zephyrproject zephyr
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

LoRaWAN 应用层时钟同步服务在 函数中解析下行消息（位于 ）。其命令处理循环仅保证一字节命令 ID 在有效范围内；对于 （即 AppTimeAns 命令），处理函数随后通过 读取 4 字节的时间修正值，并读取 1 字节的令牌（token），但未检查接收缓冲区中是否还剩余至少 5 个字节（ ）。因此，一个过短或经过构造的 AppTimeAns 消息会导致从解密后的载荷末尾之后多读最多 5 个字节。 该载荷（ ）是由注册的下行回调接收的解密后的应用层帧（ ）。要到达该处理函数，需要来自时钟同步端口的帧通过 LoR

CVSS 3.1 · Low

Affected Version Matrix 1

VendorProduct Version RangeStatus
zephyrproject zephyr 3.3.0< 4.4.2 affected
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I. Basic Information for CVE-2026-13479

Vulnerability Information
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Vulnerability Title
Out-of-bounds read in LoRaWAN clock-sync AppTimeAns downlink handler
Source: CVE Program / CVE List V5
Vulnerability Description
The LoRaWAN application-layer clock-synchronization service parses downlinks in clock_sync_package_callback() (subsys/lorawan/services/clock_sync.c). Its command loop only guarantees that the one-byte command id is in bounds; for the CLOCK_SYNC_CMD_APP_TIME (AppTimeAns) command the handler then reads a 4-byte time correction via sys_get_le32() plus a 1-byte token without checking that 5 bytes remain in the receive buffer (len - rx_pos). A short or crafted AppTimeAns therefore reads up to 5 bytes past the end of the decrypted payload. The payload (rx_buf/len) is the decrypted application frame delivered to the registered downlink callback (mcps_indication->Buffer/BufferSize). Reaching the handler requires a frame on the clock-sync port that passes LoRaWAN's MAC integrity check and FRMPayload decryption, so the practical attacker is a malicious or compromised network/application server (the designated sender of AppTimeAns) or a party holding the session keys, rather than an arbitrary radio listener. The over-read is bounded: the backing store is a fixed 255-byte static buffer, so the few stray bytes do not fault, and the read values (time_correction, token) are used only internally and never transmitted, so there is no disclosure to the attacker and no crash. The sole effect is that a stale token matching ctx.req_token can apply a garbage time_correction to the device's own clock offset (ctx.time_offset), a minor integrity impact confined to the victim's time estimate. The fix adds an explicit length check that drops a too-short AppTimeAns. Note the sibling one-byte reads in the periodicity and force-resync handlers remain unguarded with the same negligible impact.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
跨界内存读
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
zephyrproject zephyr 3.3.0 ~ 4.4.2 -

II. Public POCs for CVE-2026-13479

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III. Intelligence Information for CVE-2026-13479

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Patches & Fixes for CVE-2026-13479 (1)

Vendor Advisories for CVE-2026-13479 (1)

Same Patch Batch · zephyrproject · 2026-08-26 · 3 CVEs total

CVE-2026-13481 5.4 MEDIUM Out-of-bounds read in PTP management TLV TIME parsing in Zephyr net PTP
CVE-2026-13480 3.1 LOW Out-of-bounds read in LoRaWAN fragmented data block transport (FUOTA) downlink handler

IV. Related Vulnerabilities

Same product: zephyr
Same vendor: zephyrproject
Same weakness: CWE-125

V. Comments for CVE-2026-13479

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