How severe is CVE-2026-77406?

CVE-2026-77406 has a CVSS 4.0 base score of 8.2, rated high severity.

Is CVE-2026-77406 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-77406?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-77406 published?

CVE-2026-77406 was published on 2026-09-16.

CVE-2026-77406

CVE-2026-77406 is a high-severity vulnerability with a CVSS 4.0 base score of 8.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-195.

Key facts

Severity: High (CVSS 4.0 base score 8.2)
EPSS exploit prediction: 0% (35th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-195
Published: 2026-09-16
Last modified: 2026-09-16

Description

RabbitMQ amqp091-go is a Go AMQP 0.9.1 client. Prior to 1.13.0, Channel.Qos in channel.go accepts negative prefetchCount and prefetchSize integers and casts them directly to uint16 and uint32 fields in the basic.qos method because validateQos is absent. Values such as -1 therefore wrap to 65535 or 4294967295 instead of being rejected. An application that permits untrusted configuration of these Qos values can unintentionally request extremely large prefetch limits, allowing a broker to deliver enough queued messages to exhaust client memory and disrupt processing. This issue is fixed in version 1.13.0.

Frequently asked questions

What is CVE-2026-77406?: RabbitMQ amqp091-go is a Go AMQP 0.9.1 client. Prior to 1.13.0, Channel.Qos in channel.go accepts negative prefetchCount and prefetchSize integers and casts them directly to uint16 and uint32 fields in the basic.qos method because validateQos is absent. Values such as -1 therefore wrap to 65535 or 4294967295 instead of being rejected. An application that permits untrusted configuration of these Qos values can unintentionally request extremely large prefetch limits, allowing a broker to deliver enough queued messages to exhaust client memory and disrupt processing. This issue is fixed in version 1.13.0.
How severe is CVE-2026-77406?: CVE-2026-77406 has a CVSS 4.0 base score of 8.2, rated high severity.
Is CVE-2026-77406 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-77406?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-77406 published?: CVE-2026-77406 was published on 2026-09-16.

References

Other CWE-195 vulnerabilities

CVE-2024-25388 — High (CVSS 8.4): drivers/wlan/wlan_mgmt,c in RT-Thread through 5.0.2 has an integer signedness error and resultant buffer overflow.
CVE-2020-6096 — High (CVSS 8.1): An exploitable signed comparison vulnerability exists in the ARMv7 memcpy() implementation of GNU glibc 2.30.9000.…
CVE-2026-85441 — High (CVSS 7.5): MOOS core-moos through 10.4.0 fails to validate that serialized string lengths are non-negative in…
CVE-2026-55737 — High (CVSS 7.5): Signed to Unsigned Conversion Error and Out-of-bounds Write vulnerability in Erlang OTP erts allows an attacker who can…
CVE-2025-65495 — High (CVSS 7.5): Integer signedness error in tls_verify_call_back() in src/coap_openssl.c in OISM libcoap 4.3.5 allows remote attackers…
CVE-2026-41682 — Medium (CVSS 6.9): pupnp is an SDK for development of UPnP device and control point applications. Prior to version 1.18.5, pupnp is…

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