Skip to content
Fencer Vulns
low 3.7

CVE-2026-48524 json

PyJWT: PyJWKClient unbounded JWKS endpoint requests via attacker-controlled kid values (DoS)

published 2026-05-28 5 mo ago modified 2026-10-26 14 d ago also EUVD-2026-32916 , GHSA-fhv5-28vv-h8m8 , PYSEC-2026-177

cvss
3.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 34%
public exploits
0
none known

Summary

PyJWT is a JSON Web Token implementation in Python. Prior to 2.13.0, PyJWKClient.get_signing_key() forces a fresh HTTP request to the JWKS endpoint for every JWT with an unknown kid value, with no rate limiting. Since kid comes from the unverified token header, an attacker can trigger unlimited outbound requests. The vulnerability surfaces only when a JWKS fetch fails; an attacker can attempt to provoke that with sustained unknown-kid traffic, but the outcome depends on upstream JWKS-endpoint behavior (rate limiting, transient errors) which is beyond the attacker's control. This vulnerability is fixed in 2.13.0.

Patch / fix

  • pypi pyjwt 2.13.0
  • pyjwt_project pyjwt 2.13.0
  • pyjwt Debian 14 2.13.0-1

debian advisories DEBIAN-CVE-2026-48524

  • pyjwt Ubuntu 24.04 LTS 2.7.0-1ubuntu0.2
  • pyjwt Ubuntu 26.04 LTS 2.10.1-4ubuntu1.1

ubuntu advisories UBUNTU-CVE-2026-48524

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • python-PyJWT SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +9 more 2.8.0-150400.8.13.1
  • python-PyJWT SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 2.12.1-160000.2.1
  • python-PyJWT Linux Micro 6.1 2.12.1-slfo.1.1_2.1
  • python-PyJWT Linux Micro 6.0 2.9.0-3.1

suse advisories SUSE-SU-2026:2626-1SUSE-SU-2026:22170-1SUSE-SU-2026:22220-1SUSE-SU-2026:22138-1SUSE-SU-2026:22238-1

  • python-PyJWT openSUSE Leap 16.0 2.12.1-160000.2.1
  • python-PyJWT openSUSE Tumbleweed 2.13.0-1.1

opensuse advisories openSUSE-SU-2026:21095-1openSUSE-SU-2026:11024-1

  • python-jwt Azure Linux 3.0 2.13.0-1

azure linux advisories AZL-93027

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-48524 updated cvss 5.9

python-pyjwt: PyJWT: Denial of Service via unverified JSON Web Token key IDs

  • Red Hat Migration Toolkit for Applications 8 mta/mta-solution-server-rhel9 Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-ocp-rag-rhel9, openshift-lightspeed/lightspeed-service-api-rhel9, openshift-lightspeed/lightspeed-to-dataverse-exporter-rhel9 Red Hat AI Inference Server rhaii/vllm-cpu-rhel9, rhaii/vllm-tpu-rhel9, rhaii/vllm-cuda-rhel9, rhaiis/vllm-cpu-rhel9, rhaiis/vllm-tpu-rhel9, rhaii/vllm-gaudi-rhel9, +2 more Red Hat Ansible Automation Platform 2 python-pyjwt, automation-controller, ansible-automation-platform-26/hub-rhel9, ansible-automation-platform-26/gateway-rhel9, ansible-automation-platform-26/mcp-tools-rhel9, ansible-automation-platform-24/lightspeed-rhel8, +10 more Red Hat Enterprise Linux 9 fence-virt, fence-virtd, fence-agents, fence-virtd-cpg, fence-virtd-tcp, fence-agents-all, +51 more Red Hat Enterprise Linux 10 fence-agents-common
    +6 more products
    Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-cuda-rhel9, rhelai3/bootc-gaudi-rhel9, rhelai3/bootc-aws-cuda-rhel9, rhelai3/bootc-gcp-cuda-rhel9, rhelai3/bootc-azure-cuda-rhel9 Red Hat OpenShift AI (RHOAI) rhoai/odh-vllm-gaudi-rhel9, rhoai/odh-kserve-agent-rhel9, rhoai/odh-kserve-router-rhel9, rhoai/odh-feature-server-rhel9, rhoai/odh-llm-d-kv-cache-rhel9, rhoai/odh-llama-stack-core-rhel9, +18 more Red Hat Quay 3 quay/quay-rhel8, quay/quay-rhel9 Red Hat Satellite 6 python-pyjwt, python3-pyjwt, satellite/foreman-mcp-server-rhel9, satellite/iop-host-inventory-rhel9 Red Hat Trusted Artifact Signer rhtas/segment-reporting-rhel9, rhtas/model-transparency-rhel9 Red Hat Update Infrastructure 4 for Cloud Providers python-pyjwt
    affected: workaround, no fix available “Fix deferred”
  • Red Hat AI Inference Server rhaii/vllm-rocm-rhel9, rhaiis/vllm-cuda-rhel9, rhaiis/vllm-rocm-rhel9 Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-rocm-rhel9, rhelai3/bootc-azure-rocm-rhel9 Red Hat Hardened Images llvm, rust, llvm21
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

0.40% chance of exploitation in the next 30 days, higher than 34% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
GitHub 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
OSV 3.1 3.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

Affected packages

ecosystem package affected fixed in
pypi pyjwt
>=2.0.0, <2.13.0
<2.13.0
2.13.0

Affected products

  • jpadilla pyjwt

Classification

Weakness
  • CWE-460 Improper Cleanup on Thrown Exception
  • CWE-755 Improper Handling of Exceptional Conditions

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.