CVE-2021-41974: Tad Book3 editing book page does not perform identity verification

Q: How do I fix CVE-2021-41974?

tad book3: upgrade to 3.9. Exact commands for each OS are on this page.

Q: Is CVE-2021-41974 being exploited?

CVE-2021-41974 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-2021-41974 affect?

CVE-2021-41974 affects tad book3. Severity is critical (CVSS 9.1). Tad Book3 editing book page does not perform identity verification. Remote attackers can use the vulnerability to view and modify arbitrary content of books without permission.

Q: How urgent is CVE-2021-41974?

Priority 54/100. Critical severity; Remotely exploitable, no login, no user action

This month

CRITICAL 9.1REMOTEUPGRADE

CVE-2021-41974 is a critical-severity flaw (CVSS 9.1) affecting tad book3. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Tad Book3 editing book page does not perform identity verification. Remote attackers can use the vulnerability to view and modify arbitrary content of books without permission.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.3% (top 30%)
CISA exploited list	No
Weakness	CWE-285, CWE-306
Published	2021-10-08
Last modified	2026-06-17

Publisher (CNA): TWCERT/CC · Vendor: tad book3 project

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

Am I affected?

Timeline

2021-10-08 16:15 UTCPublished CVE record published
2026-06-17 04:09 UTCUpdated Record last modified

tad book3 project tad book3 UPGRADE

Affected: < 3.9

Fixed in: 3.9

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy tad-book3 || rpm -q tad-book3 || tad-book3 --version

2. UPGRADE to 3.9 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade tad-book3

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade tad-book3

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-2021-41974?

tad book3: upgrade to 3.9. Exact commands for each OS are on this page.

Is CVE-2021-41974 being exploited?

CVE-2021-41974 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-2021-41974 affect?

CVE-2021-41974 affects tad book3. Severity is critical (CVSS 9.1). Tad Book3 editing book page does not perform identity verification. Remote attackers can use the vulnerability to view and modify arbitrary content of books without permission.

How urgent is CVE-2021-41974?

Priority 54/100. Critical severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2021-41563 MEDIUM 6.1 UPGRADE Tad Book3 editing book function does not filter special characters

References

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