Improper Handling of Highly Compressed Data (Data Amplification) Affecting python-jwcrypto package, versions *


Severity

Recommended
low

Based on Debian security rating.

Threat Intelligence

EPSS
0.29% (22nd percentile)

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  • Snyk IDSNYK-DEBIAN12-PYTHONJWCRYPTO-15985476
  • published12 Apr 2026
  • disclosed7 Apr 2026

Introduced: 7 Apr 2026

CVE-2026-39373  (opens in a new tab)
CWE-409  (opens in a new tab)

How to fix?

There is no fixed version for Debian:12 python-jwcrypto.

NVD Description

Note: Versions mentioned in the description apply only to the upstream python-jwcrypto package and not the python-jwcrypto package as distributed by Debian. See How to fix? for Debian:12 relevant fixed versions and status.

JWCrypto implements JWK, JWS, and JWE specifications using python-cryptography. Prior to 1.5.7, an unauthenticated attacker can exhaust server memory by sending crafted JWE tokens with ZIP compression. The existing patch for CVE-2024-28102 limits input token size to 250KB but does not validate the decompressed output size. An unauthenticated attacker can cause memory exhaustion on memory-constrained systems. A token under the 250KB input limit can decompress to approximately 100MB. This vulnerability is fixed in 1.5.7.

CVSS Base Scores

version 3.1