Ubuntu 26 04 Lts
Monthly
Local privilege escalation in snap-confine - the SUID/set-capabilities helper snapd uses to build the confinement sandbox for snap applications - lets an unprivileged local user on Ubuntu 22.04, 24.04, and 26.04 LTS gain full root. The flaw only manifests where snap-confine is deployed with file capabilities (set-capabilities) instead of the traditional set-uid-root binary, where incorrect handling of ambient capabilities lets an attacker escape intended privilege boundaries and run arbitrary code as root. Reported by Canonical; no public exploit identified at time of analysis and it is not listed in CISA KEV.
Sandbox confinement bypass in Canonical snapd (snap-confine) affects all supported Ubuntu LTS releases (16.04 through 26.04) because the default seccomp templates fail to block system calls that create or set set-user-ID flags on files. A process already running inside a strictly confined snap can compile or drop a binary, mark it setuid, and then execute it to escape confinement assumptions and perform privileged actions within the container namespace. There is no public exploit identified at time of analysis and the issue is not listed in CISA KEV, but the CVSS 8.4 (scope-changed) rating reflects a genuine confinement-escape primitive.
Insecure symlink following in Canonical's ubuntu-pro-client `pro collect-logs` command allows a low-privileged local attacker to cause a root-executing diagnostic tool to read arbitrary root-owned files - including `/etc/shadow` - and bundle their contents into a support archive accessible to the attacker. All supported Ubuntu LTS releases from 16.04 through 26.04 are affected, as confirmed by Canonical's own advisory and CPE data spanning the full product history. No active exploitation has been confirmed (not in CISA KEV) and no public exploit code has been identified at time of analysis, but the attack primitive is trivially simple - standard Unix symlink creation - making exploitation straightforward once local access is obtained.
Root-level remote code execution in Canonical's ubuntu-pro-client (formerly ubuntu-advantage-tools) allows an attacker who can spoof or tamper with the Ubuntu Pro contract server response to inject arbitrary APT source lines and install malicious root-owned packages. The client builds /etc/apt/sources.list.d entries from the server's directives.suites[] and directives.aptURL fields via Python str.format() without escaping or newline filtering, and passes additionalPackages[] positionally into a root-run apt-get install. Because the component is preinstalled on supported Ubuntu Server releases and auto-attaches on cloud Ubuntu Pro images the exposure is broad; there is no public exploit identified at time of analysis and it is not listed in CISA KEV.
ubuntu-pro-client (formerly ubuntu-advantage-tools) leaks Ubuntu Pro bearer tokens to unprivileged local users via the Linux /proc filesystem on all supported Ubuntu LTS releases from 14.04 through 26.04. When the client validates APT credentials, it spawns /usr/lib/apt/apt-helper with the secret token embedded in a cleartext URL argument (https://bearer:<token>@esm.ubuntu.com/), which any local low-privileged user can read from /proc/<pid>/cmdline on default-configured systems. The stolen token enables unauthorized access to the victim's Ubuntu Pro ESM repositories. No public exploit has been identified at time of analysis, and this is not listed in CISA KEV.
TLS trust store poisoning in Canonical ADSys through v0.16.2 allows a network-positioned attacker to inject an arbitrary Root CA certificate into managed Ubuntu hosts during Active Directory Certificate Services auto-enrollment. The vendored Samba GPO extension fetches the CA certificate over plaintext HTTP from the AD CS GetCACert endpoint, and the response is registered into the system trust store via update-ca-certificates without authenticity validation. No public exploit identified at time of analysis, but the impact enables persistent decryption of TLS traffic across the host.
Local privilege escalation in snap-confine - the SUID/set-capabilities helper snapd uses to build the confinement sandbox for snap applications - lets an unprivileged local user on Ubuntu 22.04, 24.04, and 26.04 LTS gain full root. The flaw only manifests where snap-confine is deployed with file capabilities (set-capabilities) instead of the traditional set-uid-root binary, where incorrect handling of ambient capabilities lets an attacker escape intended privilege boundaries and run arbitrary code as root. Reported by Canonical; no public exploit identified at time of analysis and it is not listed in CISA KEV.
Sandbox confinement bypass in Canonical snapd (snap-confine) affects all supported Ubuntu LTS releases (16.04 through 26.04) because the default seccomp templates fail to block system calls that create or set set-user-ID flags on files. A process already running inside a strictly confined snap can compile or drop a binary, mark it setuid, and then execute it to escape confinement assumptions and perform privileged actions within the container namespace. There is no public exploit identified at time of analysis and the issue is not listed in CISA KEV, but the CVSS 8.4 (scope-changed) rating reflects a genuine confinement-escape primitive.
Insecure symlink following in Canonical's ubuntu-pro-client `pro collect-logs` command allows a low-privileged local attacker to cause a root-executing diagnostic tool to read arbitrary root-owned files - including `/etc/shadow` - and bundle their contents into a support archive accessible to the attacker. All supported Ubuntu LTS releases from 16.04 through 26.04 are affected, as confirmed by Canonical's own advisory and CPE data spanning the full product history. No active exploitation has been confirmed (not in CISA KEV) and no public exploit code has been identified at time of analysis, but the attack primitive is trivially simple - standard Unix symlink creation - making exploitation straightforward once local access is obtained.
Root-level remote code execution in Canonical's ubuntu-pro-client (formerly ubuntu-advantage-tools) allows an attacker who can spoof or tamper with the Ubuntu Pro contract server response to inject arbitrary APT source lines and install malicious root-owned packages. The client builds /etc/apt/sources.list.d entries from the server's directives.suites[] and directives.aptURL fields via Python str.format() without escaping or newline filtering, and passes additionalPackages[] positionally into a root-run apt-get install. Because the component is preinstalled on supported Ubuntu Server releases and auto-attaches on cloud Ubuntu Pro images the exposure is broad; there is no public exploit identified at time of analysis and it is not listed in CISA KEV.
ubuntu-pro-client (formerly ubuntu-advantage-tools) leaks Ubuntu Pro bearer tokens to unprivileged local users via the Linux /proc filesystem on all supported Ubuntu LTS releases from 14.04 through 26.04. When the client validates APT credentials, it spawns /usr/lib/apt/apt-helper with the secret token embedded in a cleartext URL argument (https://bearer:<token>@esm.ubuntu.com/), which any local low-privileged user can read from /proc/<pid>/cmdline on default-configured systems. The stolen token enables unauthorized access to the victim's Ubuntu Pro ESM repositories. No public exploit has been identified at time of analysis, and this is not listed in CISA KEV.
TLS trust store poisoning in Canonical ADSys through v0.16.2 allows a network-positioned attacker to inject an arbitrary Root CA certificate into managed Ubuntu hosts during Active Directory Certificate Services auto-enrollment. The vendored Samba GPO extension fetches the CA certificate over plaintext HTTP from the AD CS GetCACert endpoint, and the response is registered into the system trust store via update-ca-certificates without authenticity validation. No public exploit identified at time of analysis, but the impact enables persistent decryption of TLS traffic across the host.