pyjwt: Improper Authentication
CVE-2026-48526 is a high-severity improper authentication vulnerability in pyjwt from Jpadilla, with a CVSS 3.1 base score of 7.4 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected pyjwt versions: < 2.13.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.43% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of pyjwt you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from the organisation that assigned the CVE; 15 further products are omitted here. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N. Scored by CNA (github.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.4 | High | CNA (github.com) |
| CVSS 3.1 | 7.4 | High | CNA |
Official description
PyJWT is a JSON Web Token implementation in Python. Prior to 2.13.0, when the verifier is decoding JSON Web Tokens, while supporting both asymmetric and HMAC algorithms, the library does not validate use of JSON Web Keys in HMAC algorithm, allowing attacker to use the issuer public key as the secret key for HMAC algorithm. This vulnerability is fixed in 2.13.0.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Authentication
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
How developers prevent this class of flaw
- Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other references
- access.redhat.com/errata/RHSA-2026:25902
- access.redhat.com/errata/RHSA-2026:25928
- access.redhat.com/errata/RHSA-2026:26206
- access.redhat.com/errata/RHSA-2026:28571
- access.redhat.com/errata/RHSA-2026:30076
- access.redhat.com/errata/RHSA-2026:30088
- access.redhat.com/errata/RHSA-2026:30089
- access.redhat.com/errata/RHSA-2026:33683
- access.redhat.com/errata/RHSA-2026:34160
- access.redhat.com/errata/RHSA-2026:34365
- access.redhat.com/errata/RHSA-2026:34374
- access.redhat.com/errata/RHSA-2026:35835
- access.redhat.com/errata/RHSA-2026:35836
- access.redhat.com/errata/RHSA-2026:35837
- access.redhat.com/errata/RHSA-2026:35845
Other vulnerabilities in pyjwt
- 8.2 High severity
- 7.5 High severity
- 7.4 High severity
- 7.4 High severity
- 7.4 High severity
- 9.1 Critical severity
Recent Improper Authentication vulnerabilities
- 9.3 Critical severity
- 7.1 High severity
- 9.1 Critical severity
- 8.1 High severity
- 7.5 High severity
- 9.3 Critical severity
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