How severe is CVE-2025-46556?

CVE-2025-46556 has a CVSS score of 6.5/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2025-46556?

CVE-2025-46556 affects the following packages: mantisbt/mantisbt (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2025-46556?

Update mantisbt/mantisbt to 2.27.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-46556 is resolved across your whole dependency graph.

How do I detect CVE-2025-46556 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mantisbt/mantisbt, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2025-46556 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2025-46556 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-46556 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-46556?

CVE-2025-46556 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 36th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2025-46556?

CVE-2025-46556 is classified as CWE-770 (CWE-770). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2025-46556 published, and has it been updated?

CVE-2025-46556 was published on November 4, 2025 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘

🐘 Packagist

Not in CISA KEV

MEDIUM severity

CVE-2025-46556 — mantisbt

MEDIUMFix: mantisbt/mantisbt@c99a412

CVE-2025-46556 is a medium-severity (CVSS 6.5) CWE-770 vulnerability in mantisbt/mantisbt. A fix is available for mantisbt/mantisbt — see the affected versions and patch details below.

MantisBT is Vulnerable to Denial-of-Service (DoS) attack via Excessive Note Length

Also known asGHSA-r3jf-hm7q-qfw5

Published

Nov 4, 2025

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 5, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2025-46556.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs36th percentile — riskier than 36% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

🐘mantisbt/mantisbt

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Impact

The entire activity stream becomes unviewable (UI fails to render).
New notes cannot be displayed, effectively breaking all future collaboration on the issue.

Patches

Fixed in 2.27.2.

Workarounds

None

Credits

Thanks to Mazen Mahmoud (@TheAmazeng) for reporting the vulnerability.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`mantisbt/mantisbt`	all versions	2.27.2`composer require mantisbt/mantisbt:^2.27.2`

Affected Products

1 product · 1 configurations

Application

mantisbtmantisbt

< 2.27.2

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mantisbt/mantisbt, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update mantisbt/mantisbt to 2.27.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-46556 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

A lack of server-side validation for note length in MantisBT allows attackers to permanently corrupt issue activity logs by submitting extremely long notes (tested with 4,788,761 characters). Once such a note is added: ### Impact - The entire activity stream becomes unviewable (UI fails to render). - New notes cannot be displayed, effectively breaking all future collaboration on the issue. ### Patches Fixed in 2.27.2. ### Workarounds None ### Credits Thanks to Mazen Mahmoud (@TheAmazeng) for reporting the vulnerability.