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CVE.org (no NVD analysis yet)· CNA GitHub_M

CVE-2026-101917: PyJWT: PyJWKClient still amplifies unauthenticated JWKS fetches on unknown kid values (incomplete fix of CVE-2026-48524)

Noroxi assessment

Priority: Monitor (action score 30/100)

  • 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: 0.42% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: jpadilla pyjwt 2.14.0; azl3 python-jwt 2.13.0-1 on Azure Linux 3.0 2.15.1-1.
  • Severity is disputed: the assigning authority (CNA) scores it 5.3, NVD 7.5.

Low priority for now. Upgrade to jpadilla pyjwt 2.14.0; azl3 python-jwt 2.13.0-1 on Azure Linux 3.0 2.15.1-1 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 Python implementation of JSON Web Token standards. Prior to 2.14.0, PyJWT get_signing_key_from_jwt is affected because unknown kid misses force refreshes without a negative cache or minimum refresh interval. This occurs when unauthenticated tokens repeatedly use the same unknown kid or varying kid values absent from the cached JWKS. As a result, each cache miss causes PyJWKClient to refresh the JWKS. Consequently, attacker traffic can amplify outbound requests to the configured JWKS endpoint. This issue is fixed in version 2.14.0.

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
Sep 28, 2026
Updated
Oct 7, 2026
EPSS
0.4% · 37th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
proof of concept
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
7.5
CNA · GitHub_M
5.3
2.2 point gap

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

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.

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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

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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.

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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 2.14.0

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

    • < 2.14.0affected

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12pyjwtfrom 0—
Debian:14pyjwtbefore 2.14.0-12.14.0-1
openSUSE:Leap 16.0python-PyJWTbefore 2.12.1-160000.3.12.12.1-160000.3.1
openSUSE:Tumbleweedpython-PyJWTbefore 2.15.1-1.12.15.1-1.1
PyPIpyjwtbefore 2.14.02.14.0
SUSE:Linux Micro 6.0python-PyJWTbefore 2.9.0-159998.1.12.9.0-159998.1.1
SUSE:Linux Micro 6.1python-PyJWTbefore 2.12.1-slfo.1.1_3.12.12.1-slfo.1.1_3.1
SUSE:Linux Micro 6.2python-PyJWTbefore 2.12.1-160000.3.12.12.1-160000.3.1

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-2026-48525May 28, 2026 · PyJWT: Unauthenticated DoS via unbounded Base64URL decoding of unused payload segment in b64=false detached JWS
    21Monitor
  • ← EarlierCVE-2026-48526May 28, 2026 · PyJWT: Public-key JWK accepted as HMAC secret enables forged HS256 tokens when mixed families are allowed
    29Monitor
  • Later →CVE-2026-101918Sep 28, 2026 · PyJWT: Unauthenticated RecursionError DoS in pre-verification payload parse (PyJWKClient.get_signing_key_from_jwt / verify_signature=False)
    30Monitor

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 pyjwt2.14.0 · descriptionVendor (CNA)
azl3 python-jwt 2.13.0-1 on Azure Linux 3.02.15.1-1 · Release NotesMicrosoft (MSRC)
debian:pyjwt2.14.0-1 · Debian:14Package registry (OSV)
opensuse:python-PyJWT2.15.1-1.1 · openSUSE:TumbleweedPackage registry (OSV)
PyPI:pyjwt2.14.0Package registry (OSV)
suse:python-PyJWT2.12.1-160000.3.1 · SUSE:Linux Micro 6.2Package 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.

  1. Published
  2. Fix recordedsame day
  3. TodayOct 31, 2026+33 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

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

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.
  • No special conditions are required; it is repeatable.

If successful

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

Weakness class (CWE)

CWE-770 · Allocation of Resources Without Limits or Throttling

CVSS vector

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

nvd-primary

Attack context

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

Change log

  1. CVSS5.3 → 7.5
  2. Severitymedium → high
  3. Exploit maturity— → none
  4. Fix✗ → ✓

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

References

Show all references (1 more)

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

All records