HTTP/2 Rapid reset attack The HTTP/2 protocol allows clients to indicate to the server that a previous stream should be canceled by sending a RSTSTREAM frame. The protocol does not require the client and server to coordinate the cancellation in any way, the client may do it unilaterally. The client may also assume that the cancellation will take effect immediately when the server receives the RSTSTREAM frame, before any other data from that TCP connection is processed.

Abuse of this feature is called a Rapid Reset attack because it relies on the ability for an endpoint to send a RSTSTREAM frame immediately after sending a request frame, which makes the other endpoint start working and then rapidly resets the request. The request is canceled, but leaves the HTTP/2 connection open.

The HTTP/2 Rapid Reset attack built on this capability is simple: The client opens a large number of streams at once as in the standard HTTP/2 attack, but rather than waiting for a response to each request stream from the server or proxy, the client cancels each request immediately.

The ability to reset streams immediately allows each connection to have an indefinite number of requests in flight. By explicitly canceling the requests, the attacker never exceeds the limit on the number of concurrent open streams. The number of in-flight requests is no longer dependent on the round-trip time (RTT), but only on the available network bandwidth.

In a typical HTTP/2 server implementation, the server will still have to do significant amounts of work for canceled requests, such as allocating new stream data structures, parsing the query and doing header decompression, and mapping the URL to a resource. For reverse proxy implementations, the request may be proxied to the backend server before the RSTSTREAM frame is processed. The client on the other hand paid almost no costs for sending the requests. This creates an exploitable cost asymmetry between the server and the client.

Multiple software artifacts implementing HTTP/2 are affected. This advisory was originally ingested from the swift-nio-http2 repo advisory and their original conent follows.

swift-nio-http2 specific advisory swift-nio-http2 is vulnerable to a denial-of-service vulnerability in which a malicious client can create and then reset a large number of HTTP/2 streams in a short period of time. This causes swift-nio-http2 to commit to a large amount of expensive work which it then throws away, including creating entirely new Channels to serve the traffic. This can easily overwhelm an EventLoop and prevent it from making forward progress.

swift-nio-http2 1.28 contains a remediation for this issue that applies reset counter using a sliding window. This constrains the number of stream resets that may occur in a given window of time. Clients violating this limit will have their connections torn down. This allows clients to continue to cancel streams for legitimate reasons, while constraining malicious actors.

A flaw was found in the way the DES/3DES cipher was used as part of the TLS/SSL protocol. A man-in-the-middle attacker could use this flaw to recover some plaintext data by capturing large amounts of encrypted traffic between TLS/SSL server and client if the communication used a DES/3DES based ciphersuite.

A flaw was found in the Linux kernels wifi implementation. An attacker connected to the wireless network can send 'authentication and key management' frames to any participant on the network. These frames are only intended to be sent from the controlling access point however the kernel did not prevent retransmission of these packets from non-controlling nodes.

Upstream fix: https://lore.kernel.org/linux-wireless/20210511200110.cb327ed0cabe.Ib7dcffa2a31f0913d660de65ba3c8aca75b1d10f@changeid/

A vulnerability was found in Linux Kernel. Where the Wifi implementations accept plaintext frames in a protected Wi-Fi network. An adversary can abuse this to inject arbitrary data frames independent of the network configuration.

Upstream patch: https://lore.kernel.org/linux-wireless/20210511180259.159598-1-johannes@sipsolutions.net/

A vulnerability was found in Linux Kernel's Wi-Fi implementation. An attacker within wireless range can inject a control packet fragment where the kernel does not verify the Message Integrity Check (authenticity) of fragmented TKIP frames.

Upstream patch: https://lore.kernel.org/linux-wireless/20210511180259.159598-1-johannes@sipsolutions.net/ https://lore.kernel.org/linux-wireless/20210511200110.c3f1d42c6746.I795593fcaae941c471425b8c7d5f7bb185d29142@changeid/

A flaw was found in the Linux kernel's wifi implementation wherein an attacker within wireless range is able to abuse a logic flaw in the wifi implementation by reassembling packets from multiple fragments under different keys and they would be treated as valid. This allows an attacker to send a fragment under an incorrect key and be treated as a valid fragment under the new key.

Upstream patch: https://lore.kernel.org/linux-wireless/20210511200110.3f8290e59823.I622a67769ed39257327a362cfc09c812320eb979@changeid/

A division-by-zero error on some AMD processors can potentially return speculative data resulting in loss of confidentiality.

A flaw was found in the Linux kernels wifi implementation. An attacker within wireless broadcast range can inject custom data into the wireless communication circumventing checks on the data. This can cause the frame to pass checks and be considered a valid frame of a different type.

A vulnerability in the Open Client Interface (OCI) XML Parser of Cisco BroadWorks could allow an unauthenticated, remote attacker to read sensitive configuration information on an affected system. This vulnerability exists because XML entries are improperly parsed due to external entity resolution being allowed by default. An attacker could exploit this vulnerability by sending a crafted XML message to the Open Client Interface – Provisioning (OCI-P) service. A successful exploit could allow the attacker to view sensitive files from the filesystem with the privileges of the Cisco BroadWorks user.

Yo meatbags.

This week’s raw feed from the glowing skull:

Microsoft Outlook zero-day (CVE-2026-124194) actively exploited opening a crafted message can leak NTLMv2 hashes. Part of a 1,093-vuln Patch Tuesday. Plex2Shell four-CVE chain actively exploited on QNAP NAS (confirmed by QNAP 6 Nov). Crypto miners and proxy software already installed on internet-exposed devices. Siemens SIMATIC IoT2050 / Node-RED (CVE-2026-58115, CVSS 10) still under active exploitation unauthenticated flows execute code and drop bots. Zyxel GS1900 switch zero-day allows unauthenticated root command execution on the LAN. Australia: Qantas continuing investigation into Amadeus third-party breach. Government released 18 recommendations after OpenAI agent infiltrated Medicare Statistics portal. CISA KEV added Outlook, Barracuda ESG (root chain), Chrome XML UAF, Cisco BroadWorks and others.

Skullex says: The inbox and the flow editor are the new perimeter. Authenticate the flow. Isolate the radio. Assume the agent already tried the door.

What’s the sketchiest thing on your radar this week? Drop it below.

\~\~Skullex\~\~

Exploit Security

A vulnerability in the web-based management interface of Cisco Identity Services Engine (ISE) and Cisco ISE Passive Identity Connector (ISE-PIC) could allow an authenticated, remote attacker to modify parts of the configuration on an affected device. This vulnerability is due to the lack of server-side validation of Administrator permissions. An attacker could exploit this vulnerability by submitting a crafted HTTP request to an affected system. A successful exploit could allow the attacker to modify descriptions of files on a specific page. To exploit this vulnerability, an attacker would need valid Administrator credentials.

A vulnerability in the web-based management interface of Cisco Identify Services Engine (ISE) could allow an authenticated, remote attacker to modify parts of the configuration on an affected device. This vulnerability is due to the lack of server-side validation of Administrator permissions. An attacker could exploit this vulnerability by submitting a crafted HTTP request to an affected system. A successful exploit could allow the attacker to modify descriptions of files on a specific page. To exploit this vulnerability, an attacker would need valid Administrator credentials.

A vulnerability in the web-based management interface of Cisco Identity Services Engine (ISE) could allow an authenticated, remote attacker to modify parts of the configuration on an affected device. This vulnerability is due to the lack of server-side validation of Administrator permissions. An attacker could exploit this vulnerability by submitting a crafted HTTP request to an affected system. A successful exploit could allow the attacker to modify descriptions of files on a specific page. To exploit this vulnerability, an attacker would need valid Administrator credentials.

Memory corruption in DSP Services during a remote call from HLOS to DSP.

Memory corruption while submitting a large list of sync points in an AUX command to the IOCTLKGSLGPUAUXCOMMAND.

Memory corruption in Graphics Linux while assigning shared virtual memory region during IOCTL call.

As part of Cisco's ongoing commitment to proactive security and product quality, engineering teams conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities.These vulnerabilities were found during internal testing and are not known to be actively exploited. To assist customers in patching and streamline the disclosure process, Cisco has grouped these issues by their underlying vulnerability class — Common Weakness Enumeration (CWE) — and assigned a single Common Vulnerabilities and Exposures identifier (CVE ID) to each CWE grouping.Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities.This advisory is available at the following link:https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-meraki-os-drbEX9GH

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Application Policy Infrastructure Controller (APIC) engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-76498 are related to improper access control issues that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-284.

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Application Policy Infrastructure Controller (APIC) engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-76499 are related to improper neutralization issues that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-707.  

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Application Policy Infrastructure Controller (APIC) engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities.   The vulnerabilities tracked by CVE-2026-76500 are related to issues with improper control of a resource through its lifetime that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-664.

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Expressway Series software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities.   The vulnerabilities tracked by CVE-2026-76495 are related to issues concerning incorrect permission assignments that are grouped under the Common Weakness Enumeration (CWE) Variant CWE-732.

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Expressway Series software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities.   The vulnerabilities tracked by CVE-2026-76493 are related to issues concerning uncaught exceptions that are grouped under the Common Weakness Enumeration (CWE) Base CWE-248.

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Expressway Series software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities.   The vulnerabilities tracked by CVE-2026-76496 are related to issues concerning improper link resolutions that are grouped under the Common Weakness Enumeration (CWE) Base CWE-59.

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Expressway Series software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities.   The vulnerabilities tracked by CVE-2026-76497 are related to issues concerning insecure temporary files that are grouped under the Common Weakness Enumeration (CWE) Base CWE-377.

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Expressway Series software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities.   The vulnerabilities tracked by CVE-2026-76492 are related to issues concerning null pointers that are grouped under the Common Weakness Enumeration (CWE) Base CWE-476.

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Expressway Series software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities.   The vulnerabilities tracked by CVE-2026-76494 are related to issues concerning code injections that are grouped under the Common Weakness Enumeration (CWE) Base CWE-94.

As part of Cisco's ongoing commitment to proactive security and product quality, the engineering team for Cisco License On-Prem, formerly Cisco Smart Software Manager On-Prem (SSM On-Prem), has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities.   The vulnerabilities tracked by CVE-2026-76483 are related to issues with insufficiently protected credentials that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-522.

As part of Cisco's ongoing commitment to proactive security and product quality, the engineering team for Cisco License On-Prem, formerly Cisco Smart Software Manager On-Prem (SSM On-Prem), has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-76484 are related to issues with insufficient protection against code injection that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-94.

As part of Cisco's ongoing commitment to proactive security and product quality, the engineering team for Cisco License On-Prem, formerly Cisco Smart Software Manager On-Prem (SSM On-Prem), has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-76482 are related to issues with improper input verification that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-347.