PyJWT Issuer field partial matches allowed
Summary
The wrong string if check is run for iss checking, resulting in "acb" being accepted for "_abc_".
Details
This is a bug introduced in version 2.10.0: checking the "iss" claim
changed from isinstance(issuer, list) to isinstance(issuer, Sequence).
- if isinstance(issuer, list):
+ if isinstance(issuer, Sequence):
if payload["iss"] not in issuer:
raise InvalidIssuerError("Invalid issuer")
else:Since str is a Sequnce, but not a list, in is also used for string
comparison. This results in if "abc" not in "__abcd__": being
checked instead of if "abc" != "__abc__":.
PoC
Check out the unit tests added here: https://github.com/jpadilla/pyjwt-ghsa-75c5-xw7c-p5pm
issuer = "urn:expected"
payload = {"iss": "urn:"}
token = jwt.encode(payload, "secret")
# decode() succeeds, even though `"urn:" != "urn:expected". No exception is raised.
with pytest.raises(InvalidIssuerError):
jwt.decode(token, "secret", issuer=issuer, algorithms=["HS256"])Impact
I would say the real world impact is not that high, seeing as the signature still has to match. We should still fix it.
Software afectado
Haz clic en una tecnología para ver todas sus vulnerabilidades.
| Plataforma | Paquete | Versiones vulnerables | Corregida en |
|---|---|---|---|
| Python (PyPI) | pyjwt | >= 2.10.0, < 2.10.1 | 2.10.1 |
Referencias
- https://github.com/jpadilla/pyjwt/security/advisories/GHSA-75c5-xw7c-p5pm
- https://nvd.nist.gov/vuln/detail/CVE-2024-53861
- https://github.com/jpadilla/pyjwt/commit/1570e708672aa9036bc772476beae8bfa48f4131#diff-6893ad4a1c5a36b8af3028db8c8bc3b62418149843fc382faf901eaab008e380R366
- https://github.com/jpadilla/pyjwt/commit/33022c25525c1020869c71ce2a4109e44ae4ced1
- https://github.com/jpadilla/pyjwt
- https://pypi.org/project/pyjwt
- https://github.com/advisories/GHSA-75c5-xw7c-p5pm
- Vector CVSS
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:L/A:N- Debilidad (CWE)
CWE-697- Plataforma
- Python (PyPI)
- Paquete
pyjwt- Publicada
- 02.12.2024
- Actualizado
- 11.10.2026 15:17
Fuentes y licencias
OSV / GitHub Advisory Database - PYSEC-2026-1814 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-75c5-xw7c-p5pm - CC BY 4.0
Historial de vulnerabilidades: pyjwt
Todas las vulnerabilidades publicadas de este paquete (Python (PyPI)), de la más reciente a la más antigua. Muestra si es un fallo aislado o un paquete que hay que vigilar.
- Entradas en total
- 24
- Primera → última
- 08.2017 09.2026
- Sin corrección
- 2
- Explotada en ataques
- 0
Distribución por gravedad
- Crítica 1
- Alta 10
- Media 11
- Baja 2
Divulgaciones por año
- 2017: 1
- 2018: 0
- 2019: 0
- 2020: 0
- 2021: 0
- 2022: 1
- 2023: 0
- 2024: 1
- 2025: 1
- 2026: 20
-
PyJWT Issuer field partial matches allowed esta entrada
Identifica las vulnerabilidades de tu aplicación
Con la integración de DockRay y el inventario de software activado, DockRay compara las versiones notificadas de los componentes con las vulnerabilidades conocidas y avisa de las coincidencias confirmadas. La cobertura depende de la tecnología compatible y de los avisos disponibles.