latchset jwcrypto up to 1.5.6 JWE data amplification

CVSS Meta Temp Score
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CTI Interest Score
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5.2$0-$5k0.00

Summaryinfo

A vulnerability was found in latchset jwcrypto up to 1.5.6. It has been rated as problematic. Affected is an unknown function of the component JWE Handler. This manipulation causes data amplification. This vulnerability is registered as CVE-2026-39373. Remote exploitation of the attack is possible. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as problematic was found in latchset jwcrypto up to 1.5.6. Affected by this vulnerability is an unknown function of the component JWE Handler. The manipulation with an unknown input leads to a data amplification vulnerability. The CWE definition for the vulnerability is CWE-409. The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output. As an impact it is known to affect availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-39373 since 04/06/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 312090 (RHEL 10 / 9 : Red Hat Ansible Automation Platform 2.6 Product Security and Bug Fix Update (Important) (RHSA-2026:13508)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 1.5.7 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (312090), EUVD (EUVD-2026-19911) and CERT Bund (WID-SEC-2026-1610). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

  • Red Hat Enterprise Linux

Productinfo

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.2

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 5.3
CNA Vector (GitHub_M): 🔒

CVSSv2info

AVACAuCIA
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Data amplification
CWE: CWE-409 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 312090
Nessus Name: RHEL 10 / 9 : Red Hat Ansible Automation Platform 2.6 Product Security and Bug Fix Update (Important) (RHSA-2026:13508)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: jwcrypto 1.5.7

Timelineinfo

04/06/2026 CVE reserved
04/07/2026 +1 days Advisory disclosed
04/07/2026 +0 days VulDB entry created
05/20/2026 +43 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-fjrm-76x2-c4q4
Status: Confirmed

CVE: CVE-2026-39373 (🔒)
GCVE (CVE): GCVE-0-2026-39373
GCVE (VulDB): GCVE-100-355915
EUVD: 🔒
CERT Bund: WID-SEC-2026-1610 - Red Hat Enterprise Linux (JWCrypto und python-markdown): Mehrere Schwachstellen ermöglichen Denial of Service

Entryinfo

Created: 04/07/2026 23:22
Updated: 05/20/2026 13:11
Changes: 04/07/2026 23:22 (64), 04/07/2026 23:45 (1), 05/05/2026 00:54 (2), 05/20/2026 13:11 (7)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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