CVE-2026-77403
A Denial of Service (DoS) vulnerability exists in the AMQP client's connection negotiation logic. The AMQP specification explicitly mandates a strict minimum frame size of 4096 bytes to prevent pathological packet fragmentation. While the library defines a `frameMinSize = 4096` constant, the connection negotiation loop fails to enforce this boundary, blindly accepting whatever maximum frame size (`FrameMax`) the server advertises during the handshake. If a client connects to a malicious or compromised AMQP broker that advertises an extremely low `FrameMax` (such as 1 byte), the negotiation succeeds. Consequently, every subsequent message transmission is forced to splinter into thousands or millions of single-byte frames, causing massive CPU overhead, thread contention, and a near-instantaneous application freeze. ---
EPSS 0.52% · 44.4th percentile
Risk Scores
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| github.com | rabbitmq/amqp091-go | 0 |
| rabbitmq | amqp091-go | 0 |
Timeline
- Sep 16, 2026 Coalition ESS Score
- Sep 16, 2026 CVE Published
- Sep 17, 2026 CVE Updated
- Sep 17, 2026 EPSS Score
- Sep 18, 2026 EPSS Score
- Sep 24, 2026 EPSS Score
- Sep 26, 2026 EPSS Score
- Sep 30, 2026 EPSS Score
- Oct 2, 2026 EPSS Score
- Oct 6, 2026 EPSS Score
- Oct 8, 2026 EPSS Score
- Oct 11, 2026 EPSS Score
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-77403 advisory
- https://github.com/advisories/GHSA-xwwf-m8fg-p9q2 advisory
- https://github.com/rabbitmq/amqp091-go/security/advisories/GHSA-xwwf-m8fg-p9q2 url
- https://github.com/rabbitmq/amqp091-go/pull/353 patch
- https://github.com/rabbitmq/amqp091-go/commit/2e0a919b89f337dbf58db2bb34ab206dac354a06 patch
- https://github.com/rabbitmq/amqp091-go/releases/tag/v1.13.0 url