CVE-2026-26273: Known is a social publishing platform

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CRITICAL 9.8REMOTEUPGRADE

CVE-2026-26273 is a critical-severity flaw (CVSS 9.8) affecting known. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

Critical severity
Public exploit reference
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.0% (top 38%)
CISA exploited list	No
Weakness	CWE-200, CWE-640
Published	2026-02-13
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: withknown

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-02-13 22:16 UTCPublished CVE record published
2026-06-17 10:26 UTCUpdated Record last modified

withknown known UPGRADE

Affected: < 1.6.3

Fixed in: 1.6.3

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy known || rpm -q known || known --version

2. UPGRADE to 1.6.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade known

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade known

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Exact fixes by distribution

Composer (PHP) · idno/known · FIXED · 1.6.3 · vulnerable: <= 1.6.2 · source

composer require "idno/known:>=1.6.3"

Fedora ELN · intel-ipsec-mb · FIXED · 3.0.1-1.eln159 · FEDORA-2026-ca01077210 · source

sudo dnf upgrade --advisory=FEDORA-2026-ca01077210

Fedora 46 · complytime-providers · FIXED · 0.3.0-2.fc46 · FEDORA-2026-7c372be466 · source

sudo dnf upgrade --advisory=FEDORA-2026-7c372be466

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Write-up: github.com/idno/known/security/advisories/GHSA-78wq-6gcv-w28r

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-26273?

known: upgrade to 1.6.3. Exact commands for each OS are on this page.

Is CVE-2026-26273 being exploited?

CVE-2026-26273 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-26273 affect?

CVE-2026-26273 affects known. Severity is critical (CVSS 9.8). 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 p

How urgent is CVE-2026-26273?

Priority 63/100. Critical severity; Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-28508 HIGH 8.6 UPGRADE Idno is a social publishing platform
CVE-2026-28507 HIGH 7.2 UPGRADE Idno is a social publishing platform

References

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