Which versions of boringproxy are affected by EUVD-2026-53584?

boringproxy versions 0.10.0 and earlier contain a critical authentication bypass vulnerability affecting low-privileged users with tunnel-creation permissions.

Is there a public PoC exploit available for EUVD-2026-53584?

Yes, a public proof-of-concept exploit is available for EUVD-2026-53584. Prioritise patching immediately. EPSS: 0.2%.

How to fix or mitigate EUVD-2026-53584?

Within 24 hours, conduct an inventory of all systems running boringproxy 0.10.0 or earlier and assess network exposure of the tunnel-creation API. Within 7 days, immediately restrict tunnel-creation API access to pre-approved high-trust operator accounts only, rotate all credentials and cryptographic material stored within boringproxy databases (user tokens, SSH private keys, TLS certificates), and audit all SSH authorized_keys files on affected hosts for unauthorized public key entries. Within 30 days, apply the vendor-released patch to all instances as soon as available and perform a second rotation of all credentials; if no patched version is released, plan migration to an alternative proxy solution and complete transition before end of quarter.

boringproxy EUVD-2026-53584

Q: What is the CVSS score of EUVD-2026-53584?

EUVD-2026-53584 has a CVSS 4.0 base score of 8.5 (High). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.2%.

| CVE-2026-70615 HIGH

Improper Neutralization of CRLF Sequences ('CRLF Injection') (CWE-93)

2026-08-05 VulnCheck

GHSA-85pm-3999-r2fw

RCE Boringproxy

8.5

CVSS 4.0 · Vendor: VulnCheck

Severity by source

Vendor (VulnCheck) PRIMARY

8.5 HIGH

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

vuln.today AI

9.6 CRITICAL

Network-reachable via API (AV:N), requires only a low-privileged account (PR:L), scope changes to host OS via SSH key injection (S:C), full confidentiality and integrity compromise of host credentials and persistent access.

3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N

4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:H

Primary rating from Vendor (VulnCheck).

CVSS VectorVendor: VulnCheck

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Lifecycle Timeline

Analysis Generated

Aug 05, 2026 - 20:18 vuln.today

CVE Published

Aug 05, 2026 - 19:34 cve.org

HIGH 8.5

DescriptionCVE.org

boringproxy through 0.10.0 contains a newline injection vulnerability that allows authenticated low-privileged users with tunnel-creation permission to inject arbitrary lines into the server account's SSH authorized_keys file by supplying a percent-encoded newline character in the domain parameter of the tunnel creation endpoint. Attackers can insert an unrestricted public key entry into authorized_keys to gain persistent shell access, and subsequently read cleartext credentials from the database file including all user tokens, tunnel private keys, and TLS certificates.

AnalysisAI

Newline injection in boringproxy 0.10.0 and earlier allows authenticated low-privileged users with tunnel-creation permission to write arbitrary entries into the server's SSH authorized_keys file, achieving persistent shell access to the host. By supplying a percent-encoded newline (%0a) in the domain parameter of the tunnel creation API endpoint, an attacker inserts an unrestricted public key, then SSHs directly into the server and reads plaintext credentials - including all user tokens, tunnel private keys, and TLS certificates - from the application's database file. A public proof-of-concept exploit is available via GitHub, and no patched release has been identified at time of analysis.

Technical ContextAI

boringproxy (CPE: cpe:2.3:a:boringproxy:boringproxy:*:*:*:*:*:*:*:*) is a self-hosted reverse-proxy and HTTP tunneling tool that manages SSH tunnels for exposing local services. The vulnerability stems from CWE-93 (Improper Neutralization of CRLF Sequences / Newline Injection): the tunnel creation endpoint fails to sanitize or reject percent-encoded newline characters (%0a, decoded as LF) in the domain parameter before writing tunnel configuration data to the server's SSH authorized_keys file. Because authorized_keys is a newline-delimited flat file, injecting a newline character allows an attacker to append a fully independent key entry - with no restrictions on from= or command= directives - bypassing the intent of any existing key constraints. The secondary impact (credential theft) exploits the fact that the boringproxy process has read access to its own database file containing cleartext secrets.

RemediationAI

No vendor-released patch has been identified at time of analysis - the fix version is not confirmed from available data. Operators should immediately restrict tunnel-creation permissions to the minimum necessary set of trusted users, as this is the sole privilege gate preventing exploitation. If boringproxy must remain operational, consider placing the application behind an authentication proxy or VPN to limit who can reach the tunnel creation endpoint. Operators should audit their existing SSH authorized_keys file for unexpected entries and rotate all secrets stored in the boringproxy database (user tokens, tunnel private keys, TLS certificates) as these may have already been exfiltrated if the service was previously exposed to untrusted users. Monitor the upstream repository at https://github.com/theopaid/Remote-Code-Execution-And-Privilege-Escalation-Through-SSH-Authorized-Keys-Injection-boringproxy- and the VulnCheck advisory for patch availability. If no patch is released promptly, replacing boringproxy with an alternative tunneling solution should be considered given the severity of the impact chain.