# CVE-2021-43503

> As of 2022-08-12, CVE-2021-43503 is a vulnerability. Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2021-43503, most recently “China-Linked Threat Actor Integrates Claude Code and DeepSeek-v4-pro into Active Espionage Operations Against Government, Supply-Chain, and Financial Targets”.

**Last updated:** 2022-08-12

## What is CVE-2021-43503?

Rejected reason: DO NOT USE THIS CANDIDATE NUMBER. ConsultIDs: none. Reason: This candidate was withdrawn by its CNA. Further investigation showed that it was not a security issue. Notes: none

The identifier was first published 1619 days ago. This identifier has been marked REJECTED by its CNA, so the text above is the withdrawal record rather than a vulnerability report, and no score, product list or fix applies to it.

## Severity and exploitation probability

- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 2/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2022-04-08, last modified 2022-08-12

## Is CVE-2021-43503 being exploited?

Weaponised exploit code for CVE-2021-43503 is publicly available. 3 public proof-of-concept repositories are tracked for this identifier.

- [guoyanan1g/Laravel-vul](https://github.com/guoyanan1g/Laravel-vul) (github)
- [kang8/CVE-2021-43503](https://github.com/kang8/CVE-2021-43503) (github)
- [trickest/cve](https://github.com/trickest/cve/blob/main/2021/CVE-2021-43503.md) (trickest)

## Affected products and versions

No affected-product or package list has been recorded for CVE-2021-43503 in the tracked sources. The vendor advisory and the references below are the authoritative statement of what is affected.

## How to fix CVE-2021-43503

No vendor patch reference has been recorded for CVE-2021-43503 in the tracked sources. Watch the CNA record and the vendor advisory channel for a fix, and treat any affected deployment as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2021-43503

1 tracked threat in the Threadlinqs corpus references CVE-2021-43503, either in the campaign’s CVE list or as an indicator on the campaign record.

- [China-Linked Threat Actor Integrates Claude Code and DeepSeek-v4-pro into Active Espionage Operations Against Government, Supply-Chain, and Financial Targets](https://intel.threadlinqs.com/threat/TL-2026-1354) — HIGH · 2026-07-15

## Sources

Enriched from CVE.org, NVD, public proof-of-concept repositories. Last verified by Threadlinqs on 2026-08-03. This product uses the NVD API but is not endorsed or certified by the NVD.

No external references are recorded on this row.

Canonical: https://intel.threadlinqs.com/cve/CVE-2021-43503
Full detection coverage and IOCs for threats exploiting CVE-2021-43503 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp