CVE-2026-48990Public exploitNetwork attack vector

Resource exhaustion via unbounded RFC7797 payload acceptance

Published Jun 17, 2026 · Updated Jun 17, 2026

Uncontrolled resource consumption in Authlib joserfc 1.3.4 through 1.6.5 allows remote attackers to exhaust resources via oversized JWS payloads. RFC7797 compact and flattened JSON deserializers assign b64=false payloads without calling JWSRegistry.validate_payload_size. Exposure requires an application to accept lower-trust JWS values and rely on the library limit; successful requests can consume application resources and interrupt service.

CVSS severity5.3
Medium
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Uncontrolled resource consumption in Authlib joserfc 1.3.4 through 1.6.5 allows remote attackers to exhaust resources via oversized JWS payloads. RFC7797 compact and flattened JSON deserializers assign b64=false payloads without calling JWSRegistry.validate_payload_size. Exposure requires an application to accept lower-trust JWS values and rely on the library limit; successful requests can consume application resources and interrupt service.

The record

CVE
CVE-2026-48990
Published
Jun 17, 2026
Updated
Jun 17, 2026
Vendor
Authlib
Product
joserfc
Classifications
CWE-770, CWE-400, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 17, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.6.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Authlib · joserfcversion=< 1.6.7

Published CVSS scores

5.3GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
CWE-400Uncontrolled Resource Consumption
T1499.003Application Exhaustion Flood

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo