What is the CVSS score of CVE-2026-26273?

CVE-2026-26273 has a CVSS 3.0 base score of 9.8 (Critical). CVSS vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 0.2%.

Which versions of Known are affected by CVE-2026-26273?

A critical authentication bypass vulnerability in Known 1.6.2 and earlier allows attackers to gain unauthorized access to user accounts and sensitive data with minimal effort (CVSS 9.8).. A patch is available.

Is there a public PoC exploit available for CVE-2026-26273?

Yes, a public proof-of-concept exploit is available for CVE-2026-26273. Prioritise patching immediately. EPSS: 0.2%.

How to fix or mitigate CVE-2026-26273?

Within 24 hours: Identify all instances of Known in use and document current versions; assess whether public-facing instances exist and prioritize those for immediate remediation. Within 7 days: Deploy patch to version 1.6.3 or later on all Known installations; verify patches are applied and systems are restarted. Within 30 days: Conduct post-incident review; audit access logs for suspicious authentication activity during the vulnerability window; reset credentials for critical accounts as a precaution.

Known CVE-2026-26273

CRITICAL

Information Exposure (CWE-200)

2026-02-13 security-advisories@github.com

GHSA-78wq-6gcv-w28r

Information Disclosure Known

9.8

CVSS 3.0 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

9.8 CRITICAL

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

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 22:02 vuln.today

PoC Detected

Feb 18, 2026 - 21:01 vuln.today

Public exploit code

Patch released

Feb 18, 2026 - 21:01 nvd

Patch available

CVE Published

Feb 13, 2026 - 22:16 nvd

CRITICAL 9.8

DescriptionGitHub Advisory

Known is a social publishing platform. Prior to 1.6.3, a Critical Broken Authentication vulnerability exists in Known 1.6.2 and earlier. The application leaks the password reset token within a hidden HTML input field on the password reset page. This allows any unauthenticated attacker to retrieve the reset token for any user by simply querying the user's email, leading to full Account Takeover (ATO) without requiring access to the victim's email inbox. This vulnerability is fixed in 1.6.3.

AnalysisAI

Critical authentication bypass in Known social publishing platform 1.6.2 and earlier. Broken authentication allows unauthorized access. …

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Access

Request password reset page with target email

Exploit

Extract hidden token from HTML input field

Execution

Use token to reset victim password

Impact

Authenticate as victim account

Access

Request password reset page with target email

Exploit

Extract hidden token from HTML input field

Execution

Use token to reset victim password

Impact

Authenticate as victim account

Vulnerability AssessmentAI

Exploitation	Known versions prior to 1.6.3 with password reset functionality enabled. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment	CVSS 9.8. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario	Attacker exploits broken authentication to access accounts and content without credentials.
Remediation	Update to Known 1.6.3. Detailed patch versions, workarounds, and compensating controls in full report.

Recommended ActionAI

Within 24 hours: Identify all instances of Known in use and document current versions; assess whether public-facing instances exist and prioritize those for immediate remediation. …

Threat intelligence, references, and detailed analysis are available after sign-in.

CVE-2026-26273 vulnerability details – vuln.today

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Known CVE-2026-26273

Severity by source

CVSS VectorGitHub Advisory

Lifecycle Timeline

DescriptionGitHub Advisory

AnalysisAI

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Attack ChainAIDerived

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External POC / Exploit Code