CVE-2026-39833

Description

The in-memory keyring returned by NewKeyring() silently accepted keys with the ConfirmBeforeUse constraint but never enforced it. The key would sign without any confirmation prompt, with no indication to the caller that the constraint was not in effect. NewKeyring() now returns an error when unsupported constraints are requested.

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-358: Improperly Implemented Security Check for Standard
Reserved: 2026-04-07
Published: 2026-05-22 02:31 UTC
Last updated: 2026-05-22 18:58 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/39xxx/CVE-2026-39833.json
Linked Threat: CVE-2026-39833 — CVE-2026-39833

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: 10.03% 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-2026-31389
Assigner: Go
Published: May 22, 2026, 2:31:26 AM
Updated: May 22, 2026, 6:58:08 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: 0.0400
Vendors: golang.org/x/crypto
Products: golang.org/x/crypto/ssh/agent (0 <0.52.0)

ENISA description: The in-memory keyring returned by NewKeyring() silently accepted keys with the ConfirmBeforeUse constraint but never enforced it. The key would sign without any confirmation prompt, with no indication to the caller that the constraint was not in effect. NewKeyring() now returns an error when unsupported constraints are requested.

EUVD references (5)

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 0.14.0-15)
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 (5)

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

Web references (10)

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-2026-39833 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/79436 tenable:go.dev
https://go.dev/cl/778641 tenable:go.dev
https://nvd.nist.gov/vuln/detail/CVE-2026-39833 tenable:nvd.nist.gov
https://pkg.go.dev/vuln/GO-2026-5005 tenable:pkg.go.dev
https://www.cve.org/CVERecord?id=CVE-2026-39833 tenable:www.cve.org
https://go.dev/cl/778640 tenable:go.dev

NVD-tagged references (5)

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/778640 security@golang.org
https://go.dev/cl/778641 security@golang.org
https://go.dev/issue/79436 security@golang.org
https://groups.google.com/g/golang-announce/c/a082jnz-LvI security@golang.org
https://pkg.go.dev/vuln/GO-2026-5005 security@golang.org

Remediations (10)

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

Windows Kerberos RC4 deprecation: what will break in Active ... - 4sysops

web:4sysops.com

Starting in April 2026 , Windows updates will change the default Kerberos ticket issuance behavior to AES-SHA1 for accounts without explicit encryption settings, while RC4 can still be used where explicitly enabled. This change, driven by CVE - 2026 -20833, affects every Windows Server environment where service accounts or devices still rely on RC4. Any service account, NAS device, or legacy ...

2026-05-26 03:00 UTC
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
CISA Warns of Exploited Microsoft Defender 0-Day Flaws

web:cyberpress.org

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added two actively exploited Microsoft Defender vulnerabilities to its Known Exploited Vulnerabilities (KEV) catalog, issuing an urgent remediation directive for federal agencies with a due date of June 3, 2026 .

2026-05-26 03:00 UTC
Microsoft Patch Tuesday March 2026 - 78 Vulnerabilities Fixed ...

web:cybersecuritynews.com

Microsoft released its March 2026 Patch Tuesday security update on March 10, 2026 , addressing 78 vulnerabilities across Windows, Microsoft Office, Azure, SQL Server, and .NET. The update includes one actively exploited zero-day vulnerability and multiple Critical-rated flaws demanding immediate attention from security teams. The most urgent fix this month is CVE - 2026 -21262, the sole zero-day ...

2026-05-26 03:00 UTC
Microsoft Security Advisory CVE-2026-35433 - .NET Elevation of ...

web:github.com

Executive Summary: Microsoft is releasing this security advisory to provide information about a vulnerability in .NET 8.0, .NET 9.0, and .NET 10.0. This advisory also provides guidance on what deve...

2026-05-26 03:00 UTC
Security Update Guide - Microsoft

web:portal.msrc.microsoft.com

The Security Update Guide provides information on the latest Microsoft security updates, helping users understand and address potential vulnerabilities effectively.

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
Windows 11 April 2026 Update tested: What's new, improved and fixed

web:www.windowslatest.com

Windows 11 April 2026 update adds Narrator Copilot support, faster Settings, File Explorer fixes, and key security improvements.

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-2026-39833.json.

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