# CVE-2026-54086: SLE API for Java unbounded allocation in ISP1 PDU handling

Source: https://junglewise.ai/threats/cve-2026-54086-sle-api-for-java-is-an-implementation-of-ccsds-space-link  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-13. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-54086 · Severity: medium · CVSS 5.3 · Published 2026-10-13

SLE API for Java implements CCSDS Space Link Extension Services used for satellite and space communications. An unauthenticated attacker can send a specially crafted message with an unbounded body length declaration that causes the service to allocate excessive memory, exhaust resources, crash, or leak data, disrupting critical space communication infrastructure.

Vendors: [ESA](https://junglewise.ai/threats/vendors/esa).

## Quick answers

**Is CVE-2026-54086 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-54086 being exploited in the wild.

**How severe is CVE-2026-54086?** Medium severity, with a CVSS score of 5.3, published 13 October 2026.

**Which products and versions are affected?** ESA SLE API for Java before 5.1.7.

**Is there a fix for CVE-2026-54086?** Yes: fixed in 5.1.7. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-54086 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-54086?** Check whether you run ESA SLE API for Java 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.

## How to fix

- Fixed in 5.1.7

## Technical details

The ISP1 PDU (Protocol Data Unit) handling path in SLE API for Java prior to 5.1.7 decodes an attacker-controlled body length value and allocates a byte array without validating an upper bound, compounded by the fact that malformed or truncated input can terminate reads unexpectedly. An unauthenticated network client connecting to the SLE listening service can trigger excessive memory allocation, resource exhaustion, exceptions, and denial of service. The fix enforces reasonable upper bounds on message sizes and validates message body lengths before allocation.

## Affected products

- ESA SLE API for Java before 5.1.7

## Timeline

- 2026-10-13: disclosed
- 2026-04-21: patched

## References

- [https://github.com/esa/sleapi-j/commit/265118dfb70d1d0d991b085dcde4028c60bce4fc](https://github.com/esa/sleapi-j/commit/265118dfb70d1d0d991b085dcde4028c60bce4fc)
- [https://github.com/esa/sleapi-j/releases/tag/5.1.7](https://github.com/esa/sleapi-j/releases/tag/5.1.7)