jwcrypto token substitution can lead to authentication bypass

Exploitation

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

CVSS

not scored

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

The JWT code can auto-detect the type of token being provided, and this can lead the application to incorrect conclusions about the trustworthiness of the token. Quoting the private disclosure we received : "Under certain circumstances, it is possible to substitute a [..] signed JWS with a JWE that is encrypted with the public key that is normally used for signature validation." This substitution attack can occur only if the validating application also have access to the private key, normally used to sign the tokens, available during validation of the received JWT. The significance of this attacks depends on the use of the token, it may lead to authentication bypass or authorization bypass (respectively if claims are used to authenticate or authorize certain actions), because the attacker has full control of the data placed in the JWE and can inject any desired claim value. Several mitigating factors exist that can protect applications from this issue: - If the private key…

Published by the source

21 Sep 2022, 16:58 UTC

Last modified by the source

7 Jul 2026, 11:56 UTC

Source last checked

26 Oct 2026, 13:08 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-gwp4-mcv4-w95j

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-gwp4-mcv4-w95j

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# Patch Next advisory brief: CVE-2022-3102

Advisory: jwcrypto token substitution can lead to authentication bypass
IDs: CVE-2022-3102, GHSA-gwp4-mcv4-w95j
Record: https://patchnext.com/advisories/cve-2022-3102 (revision 2, source checked 26 Oct 2026, 13:08 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Unrated
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: jwcrypto 1.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI jwcrypto: affected < 1.4; fixed in 1.4

## Suggested inspection (read-only)
- `python -m pip show jwcrypto`: 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 jwcrypto.
- 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-gwp4-mcv4-w95j (OSV record GHSA-gwp4-mcv4-w95j lists affected ranges: PyPI jwcrypto >=0 <1.4 (fixed))
- Verified: https://github.com/advisories/GHSA-gwp4-mcv4-w95j (GitHub-reviewed advisory GHSA-gwp4-mcv4-w95j lists affected ranges: PyPI jwcrypto >=0 <1.4)

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