CVE-2026-58066: Rocket.Chat's SAML SSO before versions 8.7.0, 8.6.1, 8.5.2, 8.4.5, 8.3.7, 8.2.7, 8.1.7, 8.0.8, and 7.10.14 ver

This month

CRITICAL 9.8REMOTEUPGRADE

CVE-2026-58066 is a critical-severity flaw (CVSS 9.8) affecting rocket.chat. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Rocket.Chat's SAML SSO before versions 8.7.0, 8.6.1, 8.5.2, 8.4.5, 8.3.7, 8.2.7, 8.1.7, 8.0.8, and 7.10.14 verified XML signatures but did not bind the validated signature to samlp:Response / saml:Assertion. An attacker could submit a wrapped document carrying forged identity attributes alongside any valid signature made by the trusted IdP certificate, and log in as an arbitrary user.

Why this priority

Critical severity
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	0.4% (top 68%)
CISA exploited list	No
Weakness	CWE-287
Published	2026-07-30
Last modified	2026-08-25

Publisher (CNA): HackerOne · Vendor: rocket.chat

Last updated 2026-08-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-30 06:25 UTCPublished CVE record published
2026-08-25 18:12 UTCUpdated Record last modified

rocket.chat rocket.chat UPGRADE

Affected: < 7.10.14 · >= 8.0.0 and < 8.0.8 · >= 8.1.0 and < 8.1.7 · >= 8.2.0 and < 8.2.7 · >= 8.3.0 and < 8.3.7 · >= 8.4.0 and < 8.4.5 · >= 8.5.0 and < 8.5.2 · >= 8.6.0 and < 8.6.1

Fixed in: 7.10.14, 8.0.8, 8.1.7, 8.2.7, 8.3.7, 8.4.5, 8.5.2, 8.6.1

Safe to downgrade to: a release before 8.0.0

1. Check installed version

apt-cache policy rocket.chat || rpm -q rocket.chat || rocket.chat --version

2. UPGRADE to 7.10.14 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade rocket.chat

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade rocket.chat

Note

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

3. If no update is available yet, DOWNGRADE to a release before 8.0.0 (Debian / Ubuntu)

apt-cache madison rocket.chat sudo apt install rocket.chat=<VERSION_BEFORE_8.0.0> sudo apt-mark hold rocket.chat

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list rocket.chat sudo dnf downgrade rocket.chat-<VERSION_BEFORE_8.0.0> sudo dnf versionlock add rocket.chat

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2026-58066?

rocket.chat: upgrade to 7.10.14, 8.0.8, 8.1.7, 8.2.7, 8.3.7, 8.4.5, 8.5.2, 8.6.1. Exact commands for each OS are on this page.

Is CVE-2026-58066 being exploited?

CVE-2026-58066 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-2026-58066 affect?

CVE-2026-58066 affects rocket.chat. Severity is critical (CVSS 9.8). Rocket.Chat's SAML SSO before versions 8.7.0, 8.6.1, 8.5.2, 8.4.5, 8.3.7, 8.2.7, 8.1.7, 8.0.8, and 7.10.14 verified XML signatures but did not bind the validated signature to samlp:Response / saml:Assertion. An attacker could submit a wrapp

How urgent is CVE-2026-58066?

Priority 47/100. Critical severity; Remotely exploitable, no login, no user action

Software pages

Rocket.Chat vulnerabilities

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References

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