CVE-2026-58593: NodeBB does not bind the claimed author of an inbound ActivityPub object to the authenticated remote actor

Q: How do I fix CVE-2026-58593?

nodebb: upgrade to newer than 4.13.2. Exact commands for each OS are on this page.

Q: Is CVE-2026-58593 being exploited?

CVE-2026-58593 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-58593 affect?

CVE-2026-58593 affects nodebb. Severity is high (CVSS 7.5). NodeBB does not bind the claimed author of an inbound ActivityPub object to the authenticated remote actor. The inbound middleware verifies the HTTP-signature actor and checks the origin of object.id, but never validates that attributedTo c

Q: How urgent is CVE-2026-58593?

Priority 42/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

HIGH 7.5REMOTEUPGRADE

CVE-2026-58593 is a high-severity flaw (CVSS 7.5) affecting nodebb. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

NodeBB does not bind the claimed author of an inbound ActivityPub object to the authenticated remote actor. The inbound middleware verifies the HTTP-signature actor and checks the origin of object.id, but never validates that attributedTo corresponds to the sender. In the object mock, attributedTo is used directly as a uid, and actors.assert silently ignores numeric identifiers (filtering them out without re-deriving the uid), so a federated remo

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 79%)
CISA exploited list	No
Weakness	CWE-290, CWE-345
Published	2026-07-01
Last modified	2026-07-07

Publisher (CNA): VulnCheck · Vendor: nodebb

Last updated 2026-07-07 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-01 20:17 UTCPublished CVE record published
2026-07-07 13:16 UTCUpdated Record last modified

nodebb nodebb UPGRADE

Affected: <= 4.13.2

Fixed in: newer than 4.13.2

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 4.13.2 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade nodebb

Note

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

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-2026-58593?

nodebb: upgrade to newer than 4.13.2. Exact commands for each OS are on this page.

Is CVE-2026-58593 being exploited?

CVE-2026-58593 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-2026-58593 affect?

CVE-2026-58593 affects nodebb. Severity is high (CVSS 7.5). NodeBB does not bind the claimed author of an inbound ActivityPub object to the authenticated remote actor. The inbound middleware verifies the HTTP-signature actor and checks the origin of object.id, but never validates that attributedTo c

How urgent is CVE-2026-58593?

Priority 42/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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