Security readout for executives and security teams
Plain-English summary
PyJWT before 2.13.0 can fetch JWKS URLs through PyJWKClient using unsafe URI schemes, not just HTTP(S). Business risk is mainly for applications that let untrusted input influence JWKS or jku URLs. Impact can include limited local file access behavior, broader SSRF exposure, and possible token forgery when additional application flaws are present.
Executive priority
Treat this as a targeted authentication-stack fix, not a broad emergency. Prioritize internet-facing services and identity flows that process third-party JWTs or dynamically resolve JWKS URLs. Upgrade promptly because authentication trust decisions are affected, even though exploitation appears conditional.
Technical view
PyJWKClient passed its uri directly to urllib.request.urlopen(), inheriting handlers for HTTP, HTTPS, FTP, file, and data schemes. Without a scheme allowlist, attacker-influenced JWKS URL selection can trigger non-HTTP(S) fetches. The reported token-forgery chain requires extra application-layer weaknesses beyond the library issue.
Likely exposure
Exposure is limited to Python applications using PyJWT PyJWKClient versions before 2.13.0 where JWKS or jku URL selection can be influenced by attackers through JWT headers, configuration, OAuth parameters, or similar flows.
Exploitation context
The source bundle does not report active exploitation, and KEV is false. Exploitation is not automatic: an attacker needs influence over the PyJWKClient URI, and stronger outcomes require separate application flaws such as untrusted jku derivation or attacker-controlled JWKS placement.
Researcher notes
The important boundary is application-controlled versus attacker-influenced URI selection. The library issue expands URI handling through urllib defaults; it does not directly return fetched non-HTTP(S) content to attackers. Token forgery depends on additional weaknesses not fixed solely by this advisory.
Mitigation direction
- Upgrade PyJWT to version 2.13.0 or later.
- Restrict JWKS and jku sources to trusted HTTPS URLs only.
- Reject file, ftp, data, and other unexpected URI schemes in application logic.
- Review OAuth and JWT configuration paths for attacker-controlled JWKS URL input.
- Check the GitHub advisory for any vendor-specific guidance updates.
Validation and detection
- Inventory Python services using PyJWT and PyJWKClient.
- Confirm deployed PyJWT versions are 2.13.0 or later.
- Review code paths deriving PyJWKClient URIs from JWT headers or request parameters.
- Verify application validation rejects non-HTTPS JWKS URL schemes.
- Check authentication logs for unusual JWKS URL sources if logging exists.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
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CWE-441: Exact CWE lookup
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Open ATT&CK lookupCWE-918: Information exposure and cloud metadata lookup
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Open ATT&CK lookupCredential and access behavior lookup
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Open ATT&CK lookupCloud metadata behavior lookup
The CVE wording references SSRF or metadata access, so cloud discovery and credential material review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-48522 mapping review
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Open ATT&CK lookup- Severity
- Medium
- CVSS
- 4.2 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N1.62.5GitHub_MVulnerability scoring details
Base CVSS 3.1 score
4.2MediumVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/jpadilla/pyjwt/security/advisories/GHSA-993g-76c3-p5m4CVE reference, GitHub_M · x_refsource_CONFIRM
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.