Piccolo's current BaseUser.login implementation is vulnerable to time based user enumeration

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS

• CVE-2023-41885: 0.56% estimated exploitation activity in the next 30 days; percentile 46.44 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Short summary of the problem. Make the impact and severity as clear as possible. For example: An unsafe deserialization vulnerability allows any unauthenticated user to execute arbitrary code on the server. The current implementation of BaseUser.login leaks enough information to a malicious user such that they would be able to successfully generate a list of valid users on the platform. As Piccolo on it's own does not also enforce strong passwords (see here), these lists of valid accounts are likely to be used in a password spray attack with the outcome being attempted takeover of user accounts on the platform. The impact of this vulnerability is minor as it requires chaining with other attack vectors in order to gain more then simply a list of valid users on the underlying platform. The likelihood of this vulnerability is possible as it requires minimal skills to pull off especially given the underlying login functionality for Piccolo based sites is open source. Details Give…

Published by the source

12 Sep 2023, 13:50 UTC

Last modified by the source

16 Feb 2024, 08:10 UTC

Source last checked

26 Oct 2026, 13:12 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-h7cm-mrvq-wcfr

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-h7cm-mrvq-wcfr

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2023-41885

Advisory: Piccolo's current `BaseUser.login` implementation is vulnerable to time based user enumeration
IDs: CVE-2023-41885, GHSA-h7cm-mrvq-wcfr
Record: https://patchnext.com/advisories/cve-2023-41885 (revision 2, source checked 26 Oct 2026, 13:12 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: piccolo 0.121.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI piccolo: affected <= 0.120.0; fixed in 0.121.0

## Suggested inspection (read-only)
- `python -m pip show piccolo`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on piccolo.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-h7cm-mrvq-wcfr (OSV record GHSA-h7cm-mrvq-wcfr lists affected ranges: PyPI piccolo >=0 <0.121.0 (fixed))
- Verified: https://github.com/advisories/GHSA-h7cm-mrvq-wcfr (GitHub-reviewed advisory GHSA-h7cm-mrvq-wcfr lists affected ranges: PyPI piccolo >=0 <=0.120.0)

Commands are suggestions: review each one before running it.