Vault Vulnerable to Server-Side Request Forgery in ACME Challenge Validation via Attacker-Controlled DNS

F-VAULT-ACME-SSRF-001

Public snapshot: 26 Sep 2026. Status, releases and attribution belong to each source below; none is inferred from another record.

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Recorded evidence

5.3medium

CVE-2026-5052CVEhashicorp/vault

Vault Vulnerable to Server-Side Request Forgery in ACME Challenge Validation via Attacker-Controlled DNS

Fixed in: Vault CE 2.0.0; Vault Enterprise 2.0.0, 1.21.5, 1.20.10, 1.19.16

patched

details

Finding IDs: F-VAULT-ACME-SSRF-001
CVE: CVE-2026-5052
GHSA: GHSA-8r5m-3f66-qpr3
Status: patched
Fixed in: Vault CE 2.0.0; Vault Enterprise 2.0.0, 1.21.5, 1.20.10, 1.19.16
Recorded credit: independently identified and reported by Oleh Konko of 1seal (HCSEC-2026-06)
Note: GHSA-8r5m-3f66-qpr3 / HCSEC-2026-06; Vault ACME validation did not reject local targets for http-01 and tls-alpn-01 challenges. v2.0.0 adds isValidChallengeIP and dialACMEValidationTarget, plus challenge_permitted_ip_ranges and challenge_excluded_ip_ranges configuration.
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CVE registry state: PUBLISHED
CVE state checked: 23 Sep 2026

F-VAULT-ACME-SSRF-001: Outbound request trust. ACME validation dials attacker-controlled DNS destinations. Reviewed 24 Sep 2026. Mechanism assessed by 1seal.

Mechanism source for F-VAULT-ACME-SSRF-001

Security area (1seal assessment): Authorization. ACME validation dials attacker-controlled DNS destinations. Reviewed 24 Sep 2026.

—score not recorded

hashicorp/vault #31828Security PRhashicorp/vault

pki/acme: reject unsafe validation targets during challenge verification

enterprise merged

details

Finding IDs: F-VAULT-ACME-SSRF-001
Status: enterprise merged
Reported date: 31 Jan 2026
Rationale: hardens ACME validation so HTTP-01 and TLS-ALPN-01 challenge dials reject loopback, link-local, unspecified, multicast, and similar unsafe targets before outbound connections. public PR #31828 was opened from the reporter branch, approved by the Vault maintainer, and copied into vault-enterprise #12959, which merged on 2026-03-12.
PR opened by: @1seal
PR state observed: closed; GitHub merged: false; 2026-09-24
PR observation basis: Public PR metadata recorded in the 2026-09-24 evidence audit; not a live status feed.
Contribution boundary: @1seal opened this PR; this alone does not establish sole code authorship.

F-VAULT-ACME-SSRF-001: Outbound request trust. ACME validation dials attacker-controlled DNS destinations. Reviewed 24 Sep 2026. Mechanism assessed by 1seal.

Mechanism source for F-VAULT-ACME-SSRF-001

Security area (1seal assessment): Authorization. ACME validation dials attacker-controlled DNS destinations. Reviewed 24 Sep 2026.

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