DirectorySecurity AdvisoriesPricing
Sign in
Security Advisories

CVE-2026-39373

NVD

https://nvd.nist.gov/vuln/detail/CVE-2026-39373

Severity

5.3

Medium

CVSS V3

Eliminate CVEs with Chainguard hardened images

Build, ship, and run secure software with minimal, hardened container images — rebuilt from source daily and guarded under our industry-leading remediation SLA.

Start for free

Summary

JWCrypto: JWE ZIP decompression bomb

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.

References

  • https://nvd.nist.gov/vuln/detail/CVE-2026-39373
  • https://github.com/advisories/GHSA-fjrm-76x2-c4q4
  • https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/39xxx/CVE-2026-39373.json
  • https://github.com/latchset/jwcrypto/security/advisories/GHSA-fjrm-76x2-c4q4

Affected packages

The trusted source for open source

Talk to an expert
PrivacyTerms

Product

Chainguard ContainersChainguard LibrariesChainguard VMsChainguard OS PackagesChainguard ActionsChainguard Agent SkillsIntegrationsPricing

Solutions

FedRAMPPCI DSSCMMC 2.0SOC 2Golden ImagesCVE RemediationPublic SectorStartups

Customers

Customer StoriesChainguard Reviews

Resources

Events & WebinarsSupply Chain Security 101Chainguard CoursesDocumentationTrust CenterChainguard Slack Community

Company

About UsBlogOpen Source LeadershipPartnersNewsroomCareersLegal
© 2026 Chainguard, Inc. All Rights Reserved.
Chainguard® and the Chainguard logo are registered trademarks of Chainguard, Inc. in the United States and/or other countries.
The other respective trademarks mentioned on this page are owned by the respective companies and use of them does not imply any affiliation or endorsement.