CVE-2026-48525

mediumCVSS 5.3covered by 1 sourcefirst seen 2026-08-06

CSIRTS triage

What: PyJWT with b64=false detached JWS mode is vulnerable to unbounded Base64URL decoding of the unused payload segment, allowing unauthenticated denial of service.
Who is affected: Applications using PyJWT to validate JWS tokens with b64=false flag for payload encoding.
Urgency: Moderately urgent; unauthenticated DoS is possible via maliciously crafted JWT payloads with CVSS 5.3.
Action: Upgrade PyJWT to a patched version that bounds Base64URL decoding in detached JWS payload processing.

AI-assisted analysis generated from the source advisory — verify against the original.

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Low exploitation risk0.37% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 30% of all EPSS-scored CVEs.

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