Bug 2482752 (CVE-2026-48525)
| Summary: | CVE-2026-48525 python-pyjwt: PyJWT: Denial of Service via processing of crafted detached JWS tokens | ||
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| Product: | [Other] Security Response | Reporter: | OSIDB Bzimport <bzimport> |
| Component: | vulnerability | Assignee: | Product Security DevOps Team <prodsec-dev> |
| Status: | NEW --- | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | unspecified | CC: | alinfoot, anpicker, anthomas, aprice, bbrownin, bdettelb, bparees, cmyers, dfreiber, dnakabaa, doconnor, dranck, drow, dschmidt, dtrifiro, eborisov, ehelms, erezende, ggainey, hasun, ilpinto, jburrell, jfula, jkoehler, jlanda, jmitchel, jowilson, jsamir, juwatts, jwong, kaycoth, kshier, lball, lbrazdil, lcouzens, ljawale, lphiri, ltomasbo, luizcosta, mbarnett, mhayden, mhulan, mminar, ngough, nmoumoul, nweather, nyancey, oezr, omaciel, ometelka, osousa, pbohmill, pcreech, ptisnovs, rbiba, rbobbitt, rbryant, rchan, rhel-process-autobot, rjohnson, sdoran, simaishi, smallamp, smcdonal, sskracic, stcannon, syedriko, teagle, tmalecek, tpfromme, ttakamiy, veshanka, vkumar, watson-tool-maintainers, weaton, xdharmai, yguenane, ykashtan |
| Target Milestone: | --- | Keywords: | Security |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | --- | |
| Doc Text: |
A flaw was found in PyJWT. A remote attacker can exploit this by supplying an arbitrarily large Base64URL payload segment when verifying detached JSON Web Signature (JWS) tokens using the unencoded-payload option. This forces excessive CPU work and memory allocations, leading to a Denial of Service (DoS) against any endpoint verifying such tokens.
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | Type: | --- | |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
PyJWT is a JSON Web Token implementation in Python. From 2.8.0 to 2.12.1, when verifying detached JWS tokens using the unencoded-payload option ("b64": false, RFC 7797), PyJWT performs Base64URL decoding of the compact-serialization payload segment before enforcing the detached-payload rules. For b64=false, PyJWT later discards that decoded payload and replaces it with the caller-provided detached_payload. In practice, this turns the middle segment into an attacker-controlled “work amplifier”: a remote client can supply an arbitrarily large Base64URL payload segment that forces CPU work + memory allocations even if the signature is invalid. This creates an unauthenticated DoS vector against any endpoint that verifies detached JWS using PyJWT. This vulnerability is fixed in 2.13.0.