Key confusion through non-blocklisted public key formats in PyJWT
PyJWT is a Python implementation of RFC 7519. PyJWT supports multiple different JWT signing algorithms. With JWT, an attacker submitting the JWT token can choose the used signing algorithm. The PyJWT library requires that the application chooses what algorithms are supported. The application can specify `jwt.algorithms.get_default_algorithms()` to get support for all algorithms, or specify a single algorithm. The issue is not that big as `algorithms=jwt.algorithms.get_default_algorithms()` has to be used. Users should upgrade to v2.4.0 to receive a patch for this issue. As a workaround, always be explicit with the algorithms that are accepted and expected when decoding.
- Published
- May 24, 2022
- Updated
- Jun 17, 2026
- EPSS
- 1.4% · 71th percentile
- CWE
- CWE-327
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Report tools
Action score
30
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 1.4%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 7.5
- CNA · GitHub_M
- 7.4
- 0.1 point gap
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| pyjwt project | pyjwt | cpe:2.3:a:pyjwt_project:pyjwt |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- fedoraproject fedora35
- fedoraproject fedora36
- pyjwt project pyjwt1.5.0 and later · before 2.4.0
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
- >= 1.5.0, < 2.4.0affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | pyjwt | before 2.4.0-1 | 2.4.0-1 |
| openSUSE:Tumbleweed | python-PyJWT | before 2.10.1-2.1 | 2.10.1-2.1 |
| PyPI | pyjwt | from 1.5.0 · before 2.4.0 | 2.4.0 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP3 | python-PyJWT | before 1.7.1-150200.3.3.1 | 1.7.1-150200.3.3.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP3 | python-PyJWT | before 1.7.1-150200.3.3.1 | 1.7.1-150200.3.3.1 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP4 | python-PyJWT | before 2.4.0-150200.3.6.2 | 2.4.0-150200.3.6.2 |
| SUSE:Linux Enterprise Module for Basesystem 15 SP4 | python-PyJWT | before 2.4.0-150200.3.6.2 | 2.4.0-150200.3.6.2 |
| SUSE:Linux Enterprise Module for Public Cloud 12 | python-PyJWT | before 1.5.3-3.16.1 | 1.5.3-3.16.1 |
| SUSE:Linux Enterprise Module for Public Cloud 15 | python-PyJWT | before 1.5.3-150000.3.3.1 | 1.5.3-150000.3.3.1 |
| SUSE:Linux Enterprise Module for Public Cloud 15 SP1 | python-PyJWT | before 1.7.1-150100.6.7.1 | 1.7.1-150100.6.7.1 |
Same product
pyjwt project: all recordsOther highest-scoring records for the same primary product.
- CVE-2017-11424In PyJWT 1.5.0 and below the `invalid_strings` check in `HMACAlgorithm.prepare_key` does not account for all PEM encoded public keys.31Monitor
- CVE-2026-32597PyJWT accepts unknown `crit` header extensions (RFC 7515 §4.1.11 MUST violation)30Monitor
- CVE-2024-53861Issuer field partial matches allowed in pyjwt30Monitor
- CVE-2026-48526PyJWT: Public-key JWK accepted as HMAC secret enables forged HS256 tokens when mixed families are allowed29Monitor
- CVE-2025-45768pyjwt v2.10.1 was discovered to contain weak encryption.28Monitor
- CVE-2026-48525PyJWT: Unauthenticated DoS via unbounded Base64URL decoding of unused payload segment in b64=false detached JWS21Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:pyjwt | 2.4.0-1 · Debian:12 | Package registry (OSV) |
| opensuse:python-PyJWT | 1.7.1-150200.3.3.1 · openSUSE:Leap 15.3 | Package registry (OSV) |
| PyPI:pyjwt | 2.4.0 | Package registry (OSV) |
| suse:python-PyJWT | 1.5.3-3.16.1 · SUSE:Linux Enterprise Module for Public Cloud 12 | Package registry (OSV) |
| suse:python-PyJWT | 1.7.1-150200.3.3.1 · SUSE:Linux Enterprise Module for Basesystem 15 SP3 | Package 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.
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 researchersFinders, 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
- high · data or configuration can be modified
- Availability
- none
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- High
- Availability impact
- None
Weakness class (CWE)
CWE-327 · Use of a Broken or Risky Cryptographic AlgorithmCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
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.
Attack patterns (CAPEC)
- Encryption Brute ForcingCAPEC-20likelihood: Low · Low
- Creating a Rogue Certification Authority CertificateCAPEC-459likelihood: Medium · Very High
- Signature SpoofCAPEC-473
- Signature Spoofing by Improper ValidationCAPEC-475likelihood: Low · High
- Cryptanalysis of Cellular EncryptionCAPEC-608High
- Rooting SIM CardsCAPEC-614High
- CryptanalysisCAPEC-97likelihood: Low · Very High
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- github.com/jpadilla/pyjwt/commit/9c528670c455b8d948aff95ed50e22940d1ad3fc
- github.com/jpadilla/pyjwt/releases/tag/2.4.0
- github.com/jpadilla/pyjwt/security/advisories/GHSA-ffqj-6fqr-9h24
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5PK7IQCBVNLYJEFTPHBBPFP72H4WUFNX/
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6HIYEYZRQEP6QTHT3EHH3RGFYJIHIMAO/
- www.vicarius.io/vsociety/posts/risky-algorithms-algorithm-confusion-in-pyjwt-cve-2022-29217
Vendor advisories and official records. Exploit/PoC links are deliberately left out.