The research was conducted by Google DeepMind in collaboration with cryptography researchers from the University of California San Diego and Inria.
RSA is a widely used public-key cryptographic algorithm that relies on the mathematical difficulty of factoring large numbers. Although RSA-1024 was once considered sufficiently secure, advances in computing and cryptanalysis have made it unsuitable for protecting sensitive information. Modern systems generally use RSA keys of 2048 bits or longer.
The first major finding focused on digital signature forgery involving the PKCS#1 v1.5 padding format. Padding is additional data inserted into a message before signing to ensure that it meets the required block size. Researchers examined how this protection behaves when an attacker can influence the content of the message being signed.
The team found that when an attacker controls approximately half or more of the signed data block, the padding may no longer provide additional protection against forgery. This weakness is relevant to the PKCS#11 signing interface used by cryptographic devices, including hardware security modules.
To show the improvement, DeepMind's AI agents reproduced an earlier academic signature-forgery attack against an RSA-1024 key. The agents reduced the required computing time from approximately 1,380 CPU core-years to 391 CPU core-years, making the process around 3.5 times more efficient.
Two AI agents reportedly designed, executed and debugged the computation in less than four days, with approximately 20 messages from a human researcher, most of which involved approving their actions.
Researchers also developed a more efficient approach for situations where attackers control a smaller portion of the signed message, such as a 32-byte hash. Their theoretical calculations suggest that the proposed method could be approximately 1,600 times more efficient than the previous best approach for certain RSA-1024 signature-forgery scenarios.
The second major finding concerns RSA key factoring. RSA security depends on the difficulty of breaking down a large number into its original prime factors. The researchers developed an algorithm that could make factoring each additional RSA-1024 key approximately 30 times cheaper on average after an expensive initial computation.
However, this technique remains theoretical and has not yet been implemented. The initial computation would also require substantial resources, meaning the findings do not show an immediate practical attack against deployed encryption systems.
The researchers also highlighted important limitations of the signature-forgery technique. It requires approximately four billion signing queries in advance, does not recover the private key and does not work against devices that internally hash messages before signing.
According to Pushmeet Kohli, Vice President at Google DeepMind and Chief Scientist at Google Cloud, modern cryptographic protocols generally use RSA keys of 2048 bits or larger and remain secure against the demonstrated techniques.
The vulnerabilities, tracked as CVE-2026-116606 and CVE-2026-111560, affect Barracuda's email-filtering appliance and could allow remote attackers to bypass security restrictions and gain complete control of vulnerable systems.
According to cybersecurity firm watchTowr, which published its technical analysis, the attack chain combines an authorization bypass flaw with a command injection vulnerability. Barracuda released security patches for the issues earlier this week.
The first vulnerability, CVE-2026-116606, is an authorization bypass flaw that allows unauthenticated attackers to access a configuration restoration function and modify the appliance's global settings. The second, CVE-2026-111560, is a command injection vulnerability that enables commands to execute with root privileges.
Mandiant assigned CVSS severity scores of 9.3 and 8.6 to the two vulnerabilities, respectively.
In its technical investigation, watchTowr discovered that the authorization bypass stems from the appliance's password-change process. When a password change request fails, the system incorrectly returns a low-privilege user role instead of terminating the request completely.
The researchers also found that Barracuda's backup verification mechanism relies on a secret embedded within the appliance's code. Since this secret is not securely protected, attackers can generate a valid checksum for a specially crafted configuration backup and restore it on the targeted device.
The uploaded configuration can contain a manipulated timezone value. When the appliance processes this setting, it passes the value to a shell command that executes with root privileges.
watchTowr demonstrated the attack by successfully writing a file to the appliance with root-level permissions.
CVE-2026-116606 affects Barracuda Email Security Gateway, while CVE-2026-111560 impacts five additional products, including Load Balancer Application Delivery Controller (ADC), Message Archiver, WAF Control Center, Web Application Firewall (WAF), and Web Security Gateway (WSG).
However, the complete unauthenticated attack chain applies specifically to Email Security Gateway. Exploitation of the command injection vulnerability on the other affected products requires administrator access.
Barracuda has released security updates addressing both vulnerabilities and recommends that customers install the appropriate patches or upgrade to the latest fixed firmware versions.
As of the disclosure, neither vulnerability had been listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, and no publicly reported incidents linked the flaws to active exploitation.
The attacks targeted a maximum-severity vulnerability tracked as CVE-2026-97229, which carries a CVSS score of 10.0. Although Alpine Linux found no evidence that the attackers successfully executed malicious code or modified its software packages, the project said it could not completely rule out a breach.
Alpine Linux is a lightweight, open-source operating system widely used as the foundation for Docker container images. Its GitLab server hosts development repositories, code reviews and continuous integration (CI) jobs, including the build recipes used to produce Alpine software packages. This makes the server an important target for attackers seeking to compromise the software supply chain.
The vulnerability is caused by an integer overflow in Onigmo, the regular expression engine included in Ruby and used by GitLab's CI/CD system. If successful, this could allow the attacker to execute arbitrary code on the vulnerable server.
GitLab disclosed the vulnerability and released security fixes on October 12. However, Alpine Linux initially installed GitLab version 19.3.4 instead of the patched 19.3.5. The project later upgraded to version 19.3.6 on October 22, but the vulnerability remained because the required Ruby security patch was missing from Alpine's custom container image.
According to Alpine Linux, an attacker created a new account and began submitting specially crafted CI configurations to its GitLab server on October 20-21.
The security team recorded eight worker crashes during the attacks. Four attempts reportedly progressed partway through the exploitation process before failing to complete.
The attackers also downloaded Alpine Linux's GitLab container image, suggesting they may have been studying the server's configuration and preparing an exploit specifically designed for that environment.
The project later discovered that upgrading GitLab alone was insufficient to address the problem. The security fix required an updated version of Ruby, which was included in GitLab's official packages but was not present in Alpine's custom image.
There were doubts about a possible software supply-chain attack. If attackers had successfully compromised the GitLab server, they could potentially have accessed user information, password hashes, two-factor authentication secrets, CI/CD credentials, integration tokens and private project repositories.
The project also advised users to change passwords reused on other websites and to pull the updated alpinelinux/gitlab:19.3.6 container image published on October 27. This image includes Ruby 3.3.13, which contains the necessary security fix.