Skip to content
Noroxi
NVD / CVE Program· CNA GitHub_M

CVE-2026-48524: PyJWT: PyJWKClient unbounded JWKS endpoint requests via attacker-controlled kid values (DoS)

Noroxi assessment

Priority: Monitor (action score 14/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.40% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: jpadilla pyjwt 2.13.0; azl3 python-jwt 2.8.0-2 on Azure Linux 3.0 2.13.0-1.

Low priority for now. Upgrade to jpadilla pyjwt 2.13.0; azl3 python-jwt 2.8.0-2 on Azure Linux 3.0 2.13.0-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

LowCVSS 3.7 · v3.1—No exploit Fix available
Published
May 28, 2026
Updated
Oct 26, 2026
EPSS
0.4% · 34th percentile

Report tools

JSON

Action score

14

Monitor

Low priority for now.

CVSS
14 / 40 · 3.7 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
3.7
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-48524

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

Your free account also gets you

Running WordPress? Scan your site free with WP Lens

  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for pyjwt project records

Running WordPress? Scan your site free with WP Lens

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
pyjwt projectpyjwt

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • pyjwt project pyjwtbefore 2.13.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • jpadilla pyjwt

    • < 2.13.0affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12pyjwtfrom 0—
Debian:14pyjwtbefore 2.13.0-12.13.0-1
openSUSE:Leap 16.0python-PyJWTbefore 2.12.1-160000.2.12.12.1-160000.2.1
openSUSE:Tumbleweedpython-PyJWTbefore 2.13.0-1.12.13.0-1.1
PyPIpyjwtfrom 2.0.0 · before 2.13.02.13.0
PyPIpyjwtbefore 2.13.02.13.0
SUSE:Linux Enterprise Module for Public Cloud 15 SP4python-PyJWTbefore 2.8.0-150400.8.13.12.8.0-150400.8.13.1
SUSE:Linux Enterprise Server 16.0python-PyJWTbefore 2.12.1-160000.2.12.12.1-160000.2.1
SUSE:Linux Micro 6.0python-PyJWTbefore 2.9.0-3.12.9.0-3.1
SUSE:Linux Micro 6.1python-PyJWTbefore 2.12.1-slfo.1.1_2.12.12.1-slfo.1.1_2.1

Same product

pyjwt project: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-102268PyJWT: Asymmetric-PEM detection bypass: whitespace/line-ending-mutated public keys skip the HS/asymmetric confusion guard
    36Monitor
  • CVE-2026-102267PyJWT: PyJWKClient follows redirects when fetching JWKS
    36Monitor
  • CVE-2026-102266PyJWK accepts empty HMAC keys, bypassing PyJWT's empty-key validation
    36Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-48522May 28, 2026 · PyJWKClient: missing scheme allowlist enables SSRF + token forgery via file://, ftp://, data: schemes
    16Monitor
  • ← EarlierCVE-2026-48523May 28, 2026 · PyJWT: Algorithm allow-list bypass when decoding with `PyJWK` / `PyJWKClient` keys
    21Monitor
  • Later →CVE-2026-48525May 28, 2026 · PyJWT: Unauthenticated DoS via unbounded Base64URL decoding of unused payload segment in b64=false detached JWS
    21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
jpadilla pyjwt2.13.0 · descriptionVendor (CNA)
azl3 python-jwt 2.8.0-2 on Azure Linux 3.02.13.0-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:pyjwt2.13.0-1 · Debian:14Package registry (OSV)
opensuse:python-PyJWT2.13.0-1.1 · openSUSE:TumbleweedPackage registry (OSV)
PyPI:pyjwt2.13.0Package registry (OSV)
suse:python-PyJWT2.12.1-slfo.1.1_2.1 · SUSE:Linux Micro 6.1Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
none
Integrity
none
Availability
low · the service can be disrupted
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
Low

Weakness class (CWE)

CWE-460 · Improper Cleanup on Thrown Exception

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records