CVE-2026-39832

Description

When adding a key to a remote agent constraint extensions such as restrict-destination-v00@openssh.com were not serialized in the request. Destination restrictions were silently stripped when forwarding keys, allowing unrestricted use of the key on the remote host. The client now serializes all constraint extensions. Additionally, the in-memory keyring returned by NewKeyring() now rejects keys with unsupported constraint extensions instead of silently ignoring them.

Overview

State: PUBLISHED
Assigner (CNA): Go
CVSS severity: critical
CVSS score: 9.1 / 10
CVSS vector: AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Effective score: 9.1 / 10 CRITICAL source: CNA overview
MSRC score: 9.1 / 10 CRITICAL MS rating: Important
CWE(s): CWE-281: Improper Preservation of Permissions
Reserved: 2026-04-07
Published: 2026-05-22 02:31 UTC
Last updated: 2026-05-22 19:03 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/39xxx/CVE-2026-39832.json
Linked Threat: CVE-2026-39832 — CVE-2026-39832

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2026-05-22 04:16:22 UTC
NVD last modified: 2026-05-22 04:16:22 UTC
EPSS score: 0.0003 (probability of exploitation in next 30 days)
EPSS percentile: 8.85% vs all CVEs — higher = more likely to be exploited, as of 2026-05-24

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-31390
Assigner: Go
Published: May 22, 2026, 2:31:26 AM
Updated: May 22, 2026, 7:03:06 PM
EUVD base score (CVSS 3.1): 9.1 / 10
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EUVD-reported EPSS: 0.0700
Vendors: golang.org/x/crypto
Products: golang.org/x/crypto/ssh/agent (0 <0.52.0)

ENISA description: When adding a key to a remote agent constraint extensions such as restrict-destination-v00@openssh.com were not serialized in the request. Destination restrictions were silently stripped when forwarding keys, allowing unrestricted use of the key on the remote host. The client now serializes all constraint extensions. Additionally, the in-memory keyring returned by NewKeyring() now rejects keys with unsupported constraint extensions instead of silently ignoring them.

EUVD references (4)

Microsoft Security Response Center MSRC

Microsoft's vendor-authoritative record from the Security Update Guide — its own CVSS score, impact, severity rating, exploit assessment, and KB-article fixes. Refreshed 2026-07-28 03:00 UTC (source: CVRF).

MS severity: Important
MS CVSS base score: 9.1 / 10 (temporal 8.3)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:U
Release: 2026-May

Microsoft remediations / KB articles (2)

CBL-Mariner Releases — Vendor Fix / Security Update (fixed build 0.14.0-13)
https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade — None Available / CBL-Mariner Releases

Affected products (1)

Vendor	Product	Versions	Platforms
golang.org/x/crypto	golang.org/x/crypto/ssh/agent	`0` (affected)	—

Vendor references (4)

References embedded in the original CVE record by the assigning CNA.

Web references (9)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

None Available msrc
MSRC update guide: CVE-2026-39832 msrc
https://www.first.org/epss/ tenable:www.first.org
https://groups.google.com/g/golang-announce/c/a082jnz-LvI tenable:groups.google.com
https://go.dev/issue/79435 tenable:go.dev
https://nvd.nist.gov/vuln/detail/CVE-2026-39832 tenable:nvd.nist.gov
https://pkg.go.dev/vuln/GO-2026-5006 tenable:pkg.go.dev
https://www.cve.org/CVERecord?id=CVE-2026-39832 tenable:www.cve.org
https://go.dev/cl/778642 tenable:go.dev

NVD-tagged references (4)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

https://go.dev/cl/778642 security@golang.org
https://go.dev/issue/79435 security@golang.org
https://groups.google.com/g/golang-announce/c/a082jnz-LvI security@golang.org
https://pkg.go.dev/vuln/GO-2026-5006 security@golang.org

Remediations (10)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

Security Advisory Bulletin 064 | Ubiquiti Community

web:community.ui.com

Published: May 21, 2026 Updated: May 22, 2026 Version: 1.1 Revision: 1.1 Summary 1 of 5 A malicious actor with access to the network and high privileges could exploit an Improper Input Validation vulnerability found in UniFi OS devices to execute a Command Injection. Affected Products: UniFi OS Server (Version 5.0.6 and earlier) Mitigation : Update your UniFi OS Server to Version 5.0.8 or later ...

2026-05-26 03:00 UTC
Nvd - Cve-2026-31832

web:nvd.nist.gov

An official website of the United States government Here's how you know

2026-05-26 03:00 UTC
CVE-2026-39832 : Serialization Flaw in Remote Agent Constraints Affects ...

web:securityvulnerability.io

What is CVE-2026-39832 ? A serialization issue in OpenSSH's handling of remote agent constraints leads to the unintentional removal of destination restrictions when keys are forwarded. Specifically, extensions like restrict-destination-v00@openssh.com were not correctly serialized in requests, allowing potentially unrestricted use of keys on remote hosts. The update includes proper ...

2026-05-26 03:00 UTC
March 13, 2026—Hotpatch KB5084597 (OS Builds 26200.7982 and 26100.7982 ...

web:support.microsoft.com

This update for Windows 11, version 25H2 and 24H2 (KB5084597) incudes security improvements. To learn more about differences between security updates, optional non-security preview updates, out-of-band (OOB) updates, and continuous innovation, see Windows monthly updates explained. For information on Windows update terminology, see the different types of Windows software updates. To view the ...

2026-05-26 03:00 UTC
Google Translate

web:translate.google.com

Google's service, offered free of charge, instantly translates words, phrases, and web pages between English and over 100 other languages.

2026-05-26 03:00 UTC
April 2026 Patch Tuesday: Updates and Analysis | CrowdStrike

web:www.crowdstrike.com

Microsoft's April 2026 Patch Tuesday addresses 164 CVEs , featuring 8 Critical vulnerabilities, one exploited zero-day, and one disclosed zero-day.

2026-05-26 03:00 UTC
Oracle Critical Patch Update Advisory - April 2026

web:www.oracle.com

This Critical Patch Update contains 481 new security patches across the product families listed below. Please note that an MOS note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at April 2026 Critical Patch Update: Executive Summary and Analysis.

2026-05-26 03:00 UTC
CVE-2026-39832: Authorization Bypass vulnerability in crypto (Go)

web:www.resolvedsecurity.com

What is CVE-2026-39832 About? This vulnerability is an Authorization Bypass where key constraint extensions, such as destination restrictions, were not serialized when forwarding keys to a remote agent.

2026-05-26 03:00 UTC
CVE-2026-39832 - Info Vulnerability - TheHackerWire

web:www.thehackerwire.com

CVE-2026-39832 is a Info severity vulnerability (CVSS 0). When adding a key to a remote agent constraint extensions such as restrict-destination-v00@openssh.com were not serialized in the request.

2026-05-26 03:00 UTC
Patch Tuesday May 2026: Security Updates & CVE Analysis

web:zecurit.com

Get the complete breakdown of Microsoft's May 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .

2026-05-26 03:00 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-39832.json.

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              "confidentialityImpact": "HIGH",
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              "privilegesRequired": "NONE",
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          "url": "https://pkg.go.dev/vuln/GO-2026-5006"
        }
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      "title": "Invoking  agent constraints dropped when forwarding keys in golang.org/x/crypto/ssh/agent"
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