Is CVE-2026-39373 actively exploited?

No active exploitation of CVE-2026-39373 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-39373 be exploited remotely?

Yes. CVE-2026-39373 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-39373?

CVE-2026-39373 has a CVSS score of 5.3 (MEDIUM).

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MEDIUM

CVE-2026-39373

CWE-409Published: April 7, 2026· Updated: Apr 8, 2026

5.3

CVSS v3.1

EPSS:0.04%probability of exploitation in 30 daysPercentile:10.8th

Official 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.

NVD Source

Technical Analysis

CVE-2026-39373 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.