CVE-2021-28373: The auth_internal plugin in Tiny Tiny RSS (aka tt-rss) before 2021-03-12 allows an attacker to log in via the

Q: How do I fix CVE-2021-28373?

tiny tiny rss: upgrade to 2021-03-12. Exact commands for each OS are on this page.

Q: Is CVE-2021-28373 being exploited?

CVE-2021-28373 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-2021-28373 affect?

CVE-2021-28373 affects tiny tiny rss. Severity is high (CVSS 7.5). The auth_internal plugin in Tiny Tiny RSS (aka tt-rss) before 2021-03-12 allows an attacker to log in via the OTP code without a valid password. NOTE: this issue only affected the git master branch for a short time. However, all end users a

Q: How urgent is CVE-2021-28373?

Priority 46/100. High severity; Remotely exploitable, no login, no user action

This month

HIGH 7.5REMOTEUPGRADE

CVE-2021-28373 is a high-severity flaw (CVSS 7.5) affecting tiny tiny rss. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The auth_internal plugin in Tiny Tiny RSS (aka tt-rss) before 2021-03-12 allows an attacker to log in via the OTP code without a valid password. NOTE: this issue only affected the git master branch for a short time. However, all end users are explicitly directed to use the git master branch in production. Semantic version numbers such as 21.03 appear to exist, but are automatically generated from the year and month. They are not releases.

Why this priority

High severity
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	0.9% (top 39%)
CISA exploited list	No
Weakness	CWE-863
Published	2021-03-13
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: tt-rss

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

Am I affected?

Timeline

2021-03-13 21:15 UTCPublished CVE record published
2026-06-17 03:46 UTCUpdated Record last modified

tt-rss tiny tiny rss UPGRADE

Affected: < 2021-03-12

Fixed in: 2021-03-12

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy tiny-tiny-rss || rpm -q tiny-tiny-rss || tiny-tiny-rss --version

2. UPGRADE to 2021-03-12 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade tiny-tiny-rss

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade tiny-tiny-rss

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-2021-28373?

tiny tiny rss: upgrade to 2021-03-12. Exact commands for each OS are on this page.

Is CVE-2021-28373 being exploited?

CVE-2021-28373 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-2021-28373 affect?

CVE-2021-28373 affects tiny tiny rss. Severity is high (CVSS 7.5). The auth_internal plugin in Tiny Tiny RSS (aka tt-rss) before 2021-03-12 allows an attacker to log in via the OTP code without a valid password. NOTE: this issue only affected the git master branch for a short time. However, all end users a

How urgent is CVE-2021-28373?

Priority 46/100. High severity; Remotely exploitable, no login, no user action

Software pages

Git vulnerabilities

Related CVEs

CVE-2020-25789 MEDIUM 6.1 UPGRADE An issue was discovered in Tiny Tiny RSS (aka tt-rss) before 2020-09-16
CVE-2020-25788 HIGH 8.1 UPGRADE An issue was discovered in Tiny Tiny RSS (aka tt-rss) before 2020-09-16
CVE-2020-25787 CRITICAL 9.8 UPGRADE An issue was discovered in Tiny Tiny RSS (aka tt-rss) before 2020-09-16
CVE-2017-16896 CRITICAL 9.8 DOWNGRADE A SQL injection in classes/handler/public.php in the forgotpass component of Tiny Tiny RSS 17.4 exists via the
CVE-2017-1000035 MEDIUM 6.1 MITIGATE Tiny Tiny RSS before 829d478f is vulnerable to XSS window.opener attack

References

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