RabbitMQ amqp091-go: Protocol Desynchronization and Frame Injection via Integer Overflow in readLongstr

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

9.5 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H · score source

EPSS

• CVE-2026-77411: 0.52% estimated exploitation activity in the next 30 days; percentile 44.48 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary A critical stream desynchronization vulnerability has been identified in the AMQP wire-protocol parser. When parsing a long string (readLongstr) within a table field, providing a length that exceeds the maximum signed 32-bit integer (2^31 - 1, or roughly 2.1 GiB) triggers an improper error-handling condition. The parser abruptly aborts the read and returns a success status ("",nil) without consuming the specified bytes from the underlying network buffer. This causes all subsequent read operations to become misaligned. The parser interprets arbitrary offsets within the remaining payload bytes as valid AMQP frame headers, leading to potential Remote Code Execution (RCE), data injection, or complete connection hijacking. Vulnerability Details The vulnerability exists within the bounds-checking logic of the readLongstr function: When length evaluates to a value greater than 0x7FFFFFFF: 1. The function executes a silent return statement. 2. Because Go utilizes named or zero-value…

Published by the source

17 Sep 2026, 17:04 UTC

Last modified by the source

1 Oct 2026, 20:45 UTC

Source last checked

26 Oct 2026, 15:29 UTC

1. Revision 4 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-c5pq-fr2g-9jpf

2. Revision 3 · amended · 25 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GO-2026-6496

4. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-c5pq-fr2g-9jpf

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# Patch Next advisory brief: CVE-2026-77411

Advisory: RabbitMQ amqp091-go: Protocol Desynchronization and Frame Injection via Integer Overflow in readLongstr
IDs: CVE-2026-77411, GHSA-c5pq-fr2g-9jpf
Record: https://patchnext.com/advisories/cve-2026-77411 (revision 4, source checked 26 Oct 2026, 15:29 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/rabbitmq/amqp091-go 1.13.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/rabbitmq/amqp091-go: affected < 1.13.0; fixed in 1.13.0

## Suggested inspection (read-only)
- Go github.com/rabbitmq/amqp091-go: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/rabbitmq/amqp091-go.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-c5pq-fr2g-9jpf (OSV record GHSA-c5pq-fr2g-9jpf lists affected ranges: Go github.com/rabbitmq/amqp091-go >=0 <1.13.0 (fixed))
- Verified: https://osv.dev/vulnerability/GO-2026-6496 (OSV record GO-2026-6496 lists affected ranges: Go github.com/rabbitmq/amqp091-go >=0 <1.13.0 (fixed))
- Verified: https://github.com/advisories/GHSA-c5pq-fr2g-9jpf (GitHub-reviewed advisory GHSA-c5pq-fr2g-9jpf lists affected ranges: Go github.com/rabbitmq/amqp091-go >=0 <1.13.0)

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