Is CVE-2026-48990 in the CISA KEV catalog?

No. CVE-2026-48990 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-48990?

CVE-2026-48990 has a CVSS v3 base score of 5.3 (MEDIUM).

What is the EPSS score for CVE-2026-48990?

CVE-2026-48990 has an EPSS score of 0.16% (6th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-48990?

Upgrade joserfc on debian unstable to 1.6.8-1 or later.

CVE & CISA-KEV Catalog

CVE-2026-48990

MEDIUM

5.3

CVSS v3

NVD

Description

joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. In versions 1.3.4 through 1.6.5, joserfc accepts oversized RFC7797 b64=false JWS payloads without applying JWSRegistry.max_payload_length, which can lead to resource exhaustion. The normal JWS compact and flattened JSON paths reject payloads above the configured payload-size limit with ExceededSizeError. The RFC7797 unencoded payload paths do not make the same check. A valid b64=false compact or flattened JSON JWS can therefore deserialize successfully with a payload larger than JWSRegistry.max_payload_length. Applications that accept lower-trust JWS values and rely on joserfc to reject oversized token content during verification have a moderate availability risk. This issue has been fixed in version 1.6.7.

CWE-400Resource Exhaustion CWE-770Allocation of Resources Without Limits or Throttling

How to fix

Remediation Available

joserfcDebian

Fixed in:1.6.8-1CVE-2026-48990

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityLow

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

Exploit Intelligence

0.16%probability of exploitation in 30 days

6thpercentile

Low risk: more likely to be exploited than 6% of all known CVEs.

References

Other references2

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-23.