rallly: Insufficient Entropy
CVE-2025-47781 is a critical-severity insufficient entropy vulnerability in rallly from Lukevella, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected rallly versions: <= 3.11.2. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.64% chance of exploitation within 30 days, higher than 51% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of rallly you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA (github.com).
Official description
Rallly is an open-source scheduling and collaboration tool. Versions up to and including 3.22.1 of the application features token based authentication. When a user attempts to login to the application, they insert their email and a 6 digit code is sent to their email address to complete the authentication. A token that consists of 6 digits only presents weak entropy however and when coupled with no token brute force protection, makes it possible for an unauthenticated attacker with knowledge of a valid email address to successfully brute force the token within 15 minutes (token expiration time) and take over the account associated with the targeted email address. All users on the Rallly applications are impacted. As long as an attacker knows the user's email address they used to register on the app, they can systematically take over any user account. For the authentication mechanism to be safe, the token would need to be assigned a complex high entropy value that cannot be bruteforced within reasonable time, and ideally rate limiting the /api/auth/callback/email endpoint to further make brute force attempts unreasonable within the 15 minutes time. As of time of publication, no patched versions are available.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Insufficient Entropy
The product uses an algorithm or scheme that produces insufficient entropy, leaving patterns or clusters of values that are more likely to occur than others.
How developers prevent this class of flaw
- Determine the necessary entropy to adequately provide for randomness and predictability. This can be achieved by increasing the number of bits of objects such as keys and seeds.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in rallly
- 8.1 High severity
- 8.1 High severity
- 7.1 High severity
- 8.1 High severity
- 9.1 Critical severity
Recent Insufficient Entropy vulnerabilities
- 7.7 High severity
- 7.5 High severity
- 9.8 Critical severity
- 8.2 High severity
- 8.0 High severity
- 9.8 Critical severity
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