CVE-2026-39373
Medium
Description
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.
SeverityMedium
CVSS5.3
Exploit probability—
ProductLatchset Jwcrypto
PublishedApr 7, 2026
First seenApr 7, 2026
Weakness typeCWE-409CWE-409
How to fix
Update
- latchset jwcrypto1.5.7 or later
- jwcrypto1.5.7 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| latchset jwcrypto | v < 1.5.7 | 1.5.7 |
| jwcryptoPyPI | v < 1.5.7 | 1.5.7 |
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