Amazon Linux 2 Security Advisory: ALAS2-2026-3254
Advisory Released Date: 2026-04-30
Advisory Updated Date: 2026-04-30
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. (CVE-2026-39373)
Affected Packages:
python-jwcrypto
Note:
This advisory is applicable to Amazon Linux 2 (AL2) Core repository. Visit this FAQ section for the difference between AL2 Core and AL2 Extras advisories.
Issue Correction:
Run yum update python-jwcrypto or yum update --advisory ALAS2-2026-3254 to update your system.
noarch:
python-jwcrypto-0.4.2-1.amzn2.0.3.noarch
src:
python-jwcrypto-0.4.2-1.amzn2.0.3.src