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Fencer Intel
high 8.1

CVE-2019-9710 json

Webargs mishandles concurrent JSON parsing

published 7y ago modified 4mo ago also GHSA-8554-jxcw-454q , PYSEC-2019-139 , EUVD-2019-0159

cvss
8.1
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 66%
public exploits
0
none known

Summary

An issue was discovered in webargs before 5.1.3, as used with marshmallow and other products. JSON parsing uses a short-lived cache to store the parsed JSON body. This cache is not thread-safe, meaning that incorrect JSON payloads could have been parsed for concurrent requests.

Patch / fix

  • pypi webargs 5.1.3
  • webargs_project webargs 5.1.3

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Exploit prediction

1.12% chance of exploitation in the next 30 days, higher than 66% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/marshmallow-code/webargs/issues/371 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 8.1 CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P
GitHub 3.0 8.1 CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
pypi webargs
<5.1.3
5.1.3

Classification

Weakness
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.