Vulnerability in Latchset Jwcrypto
CVE-2026-39373
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.
EPSS: 0.003 (21.7th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
Affected products
- Latchset Jwcrypto — versions < 1.5.7
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-39373?
- CVE-2026-39373 is a medium-severity vulnerability in Latchset Jwcrypto, classified under Improper Handling of Highly Compressed Data (Data Amplification). CVSS score: 5.3/10. Published 2026-04-07.
- How severe is CVE-2026-39373?
- Medium severity. CVSS v3 base score is 5.3 out of 10.