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CVE-2026-39373— JWCrypto: JWE ZIP decompression bomb

Quick assessment

Affected
latchset jwcrypto
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

JWCrypto是JWCrypto开源的一个 Javascript 对象签名和加密 (JOSE) Web 标准的实现。 JWCrypto 1.5.7之前版本存在安全漏洞，该漏洞源于对解压缩输出大小验证不足，可能导致未经身份验证的攻击者耗尽服务器内存。

CVSS 5.3 · Medium EPSS 0.29% · P22
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I. Basic Information for CVE-2026-39373

Vulnerability Information
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Vulnerability Title
JWCrypto: JWE ZIP decompression bomb
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
对高度压缩数据的处理不恰当(数据放大攻击)
Source: CVE Program / CVE List V5
Vulnerability Title
JWCrypto 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
JWCrypto是JWCrypto开源的一个 Javascript 对象签名和加密 (JOSE) Web 标准的实现。 JWCrypto 1.5.7之前版本存在安全漏洞，该漏洞源于对解压缩输出大小验证不足，可能导致未经身份验证的攻击者耗尽服务器内存。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
latchset jwcrypto < 1.5.7 -

II. Public POCs for CVE-2026-39373

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III. Intelligence Information for CVE-2026-39373

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Vendor Advisories for CVE-2026-39373 (1)

IV. Related Vulnerabilities

Same product: jwcrypto
Same vendor: latchset
Same weakness: CWE-409

V. Comments for CVE-2026-39373

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