Portainer: JWT accepted in URL query leaks tokens to logs and referers

Exploitation

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

CVSS 4.0

7.7 · CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-44883: 0.29% estimated exploitation activity in the next 30 days; percentile 21.68 (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 Portainer's authentication middleware accepts JWT bearer tokens passed as the ?token=<JWT URL query parameter on any authenticated API endpoint, in addition to the standard Authorization: Bearer header. URLs are recorded in reverse-proxy access logs, browser history, and HTTP Referer headers on outbound navigation, so any JWT passed this way can be harvested by anyone with access to those logs or by an external site the user subsequently visits. A leaked token grants the full privileges of the user it was issued to, until the token expires (default 8 hours, configurable). The ?token= parameter was used by Portainer's browser-based container attach, exec, and pod shell features, so any user with exec or attach rights on a container was exposed — not only administrators. Severity High Attack complexity is High because exploitation depends on the attacker obtaining a leaked token from a log, referer, or shared URL. Once obtained, a leaked token grants the privileges of the user…

Published by the source

14 May 2026, 16:33 UTC

Last modified by the source

9 Jun 2026, 10:25 UTC

Source last checked

26 Oct 2026, 15:23 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-jvp4-q659-95mj

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# Patch Next advisory brief: CVE-2026-44883

Advisory: Portainer: JWT accepted in URL query leaks tokens to logs and referers
IDs: CVE-2026-44883, GHSA-jvp4-q659-95mj
Record: https://patchnext.com/advisories/cve-2026-44883 (revision 1, source checked 26 Oct 2026, 15:23 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/portainer/portainer 2.41.0, 2.39.2, 2.33.8. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/portainer/portainer: affected >= 2.33.0, < 2.33.8; >= 2.39.0, < 2.39.2; >= 2.40.0, < 2.41.0; fixed in 2.39.2, 2.33.8, 2.41.0

## Suggested inspection (read-only)
- Go github.com/portainer/portainer: check the installed version with your package manager.

## 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 github.com/portainer/portainer.
- 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://github.com/advisories/GHSA-jvp4-q659-95mj (GitHub-reviewed advisory GHSA-jvp4-q659-95mj lists affected ranges: Go github.com/portainer/portainer >=2.33.0 =2.39.0 =2.40.0 <2.41.0)

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