# CVE-2026-59323: Spring Micrometer Tracing denial of service in W3C baggage parsing

Source: https://junglewise.ai/threats/cve-2026-59323-spring-micrometer-tracing-denial-of-service-in-w3c-baggage  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-21. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-59323 · Severity: medium · CVSS 5.3 · Published 2026-08-21

Spring Micrometer Tracing is a library used to collect and track distributed requests across microservices. Applications using W3C baggage propagation with the Brave bridge are vulnerable to denial of service when processing specially crafted baggage headers. An attacker can send malicious requests that cause unbounded memory allocation, exhausting server resources and disrupting service availability.

Vendors: [Spring](https://junglewise.ai/threats/vendors/spring).

## Quick answers

**Is CVE-2026-59323 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-59323 being exploited in the wild.

**How severe is CVE-2026-59323?** Medium severity, with a CVSS score of 5.3, published 21 August 2026.

**Which products and versions are affected?** Spring Micrometer Tracing 1.4.13 and earlier, 1.5.0-1.5.12, 1.6.0-1.6.6, 1.7.0.

**Is there a fix for CVE-2026-59323?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-59323 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-59323?** Check whether you run Spring Micrometer Tracing at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a denial of service (DoS) caused by unbounded object allocation in the W3C baggage header extraction logic within Micrometer Tracing's Brave bridge. When processing incoming baggage headers, the application fails to enforce limits on the number or size of extracted objects, allowing an attacker to send crafted headers that trigger excessive memory consumption. The vulnerability is network-reachable and requires no authentication; any attacker can send HTTP requests with malicious baggage headers to trigger resource exhaustion. Patches are available in Micrometer Tracing 1.6.7, 1.5.13, and 1.7.1 and later.

## Affected products

- Spring Micrometer Tracing 1.4.13 and earlier, 1.5.0-1.5.12, 1.6.0-1.6.6, 1.7.0

## Timeline

- 2026-08-21: disclosed

## References

- [https://spring.io/security/cve-2026-59323](https://spring.io/security/cve-2026-59323)