Last updated: August 19, 2026 at 1:47 AM UTC
All 741 Vulnerability 286 Breach 129 Threat 319 Defense 7
Tag: authentication-bypass (14 articles)Clear

Exploited macOS Screen Sharing flaw gives attackers root to plant miners

The Netherlands cyber agency warned that attackers are exploiting a recently patched macOS flaw to gain root on internet-exposed Macs and install cryptocurrency miners. Tracked as CVE-2026-65400 and scored 9.8, the authentication flaw in the Screen Sharing component lets a network attacker authenticate to the built-in remote desktop service, which uses VNC on port 5900, without valid credentials due to flawed state management. Apple fixed it in emergency updates on August 6 for macOS Tahoe, Sequoia, and Sonoma. Screen Sharing is off by default, but any Mac with it enabled and reachable from the internet is at high risk, and several have already been compromised to run Monero miners.

Check
Install Apple's August macOS updates on all Macs, and confirm Screen Sharing is disabled or that port 5900 is not reachable from the internet on any system where remote desktop is enabled.
Affected
Macs with Screen Sharing enabled and reachable from the internet on unpatched macOS Tahoe, Sequoia, or Sonoma (CVE-2026-65400); a network attacker can authenticate without credentials and gain root.
Fix
Update macOS, disable Screen Sharing where it is not needed, restrict remote desktop access to trusted networks or a VPN, and check exposed Macs for unauthorized access and cryptominer processes.

Attackers exploit N-able RMM auth bypass, and the first fix did not hold

N-able is warning that attackers exploited an authentication bypass in N-central, the remote monitoring and management platform used by managed service providers and IT teams to administer customer endpoints. The flaw, CVE-2026-18556, allows unauthenticated administrative account takeover, and N-able's initial fix in one release proved incomplete: it found another way to exploit the same weakness, tracked as CVE-2026-18577, that widened the affected range. After taking over a server, attackers used its remote-control feature to reach managed endpoints and installed Cloudflare tunnels as services, which kept access alive even after the route through the N-central server was cut. Build 2026.3.1.7 is the first unaffected version.

Check
Upgrade N-central to build 2026.3.1.7 immediately, then hunt managed endpoints for unexpected Cloudflare tunnel services and other persistence, since patching the server does not remove footholds already placed.
Affected
Managed service providers and IT teams running N-able N-central before build 2026.3.1.7 (CVE-2026-18556, CVE-2026-18577); an unauthenticated attacker can take over the server and pivot to every managed customer endpoint.
Fix
Apply the hotfix, review N-central and endpoint logs for unauthorized access and tunnel installs, revoke and rebuild trust where compromise is found, and restrict management platform exposure to the internet.

Check Point patches exploited SmartConsole flaw giving attackers full admin access

Check Point has fixed an actively exploited flaw in SmartConsole, the graphical admin panel used to manage its security products. CVE-2026-16232, rated 9.3, is an authentication bypass letting an unauthenticated remote attacker obtain a login token and authenticate with administrator privileges, after which they can alter security configuration and policy on a Security Management or Multi-Domain Management server. Exploitation requires the management server to be reachable from the internet with no restrictions on trusted GUI clients. The same update fixes a second critical authentication bypass and a Gaia Portal issue letting read-only users run commands as root.

Check
Install the July 22 Jumbo hotfix on Security Management and Multi-Domain Management servers, then restrict trusted GUI clients to approved addresses and firewall management access to known sources.
Affected
Organizations running Check Point Security Management or Multi-Domain Management with the console reachable from the internet (CVE-2026-16232); attackers gain administrator access and can rewrite the security policy protecting the network.
Fix
Apply the hotfix, limit trusted clients to specific addresses, keep management interfaces off the public internet, and review policy changes and administrator logins for unauthorized modifications.

Qilin ransomware crews break in through a Palo Alto VPN authentication bypass

Arctic Wolf Labs investigated multiple intrusions in June that began by exploiting an authentication bypass in Palo Alto Networks PAN-OS and ended in Qilin ransomware. CVE-2026-0257 affects the portal and gateway components and lets an unauthenticated remote attacker establish a VPN session without valid credentials, but only where authentication override cookies are enabled alongside specific certificate configurations. That narrow precondition makes it easy to assume you are unaffected without checking. The flaw is patched. Because it grants VPN access rather than code execution, the intrusions look like ordinary remote logins at the start, which delays detection until ransomware is deployed.

Check
Confirm PAN-OS is patched against this flaw and check whether authentication override cookies are enabled with the certificate configurations that make it exploitable, since the precondition is easy to overlook.
Affected
Organizations running unpatched PAN-OS portal or gateway components with authentication override cookies enabled (CVE-2026-0257); attackers establish VPN sessions without credentials, and Qilin affiliates have used this for initial access.
Fix
Patch PAN-OS, disable authentication override cookies where not required, require multi-factor authentication on VPN access, and hunt for VPN sessions lacking a corresponding authentication event or coming from unexpected locations.

Critical BeyondTrust flaws let attackers bypass authentication on remote-access appliances

BeyondTrust has patched two critical flaws in its Remote Support and Privileged Remote Access products that let an unauthenticated, network-positioned attacker bypass authentication and reach the appliance, including accounts with elevated privileges. The bugs, CVE-2026-40138 and CVE-2026-40139, both rated 9.2, sit in the authentication subsystem and depend on a specific authentication configuration being enabled. Cloud-hosted customers were patched automatically in April, but self-hosted deployments on version 25.3.2 or earlier need to update themselves. BeyondTrust has not reported exploitation, but its remote-support products have a history of being attacked, including flaws used to breach the US Treasury and to deploy ransomware, so internet-facing appliances should be patched quickly.

Check
Identify any self-hosted BeyondTrust Remote Support or Privileged Remote Access appliances, confirm their versions, prioritize internet-facing ones, and review whether the specific authentication configuration these flaws require is enabled.
Affected
Self-hosted BeyondTrust Remote Support and Privileged Remote Access appliances on version 25.3.2 or earlier (CVE-2026-40138, CVE-2026-40139); an unauthenticated attacker can bypass authentication and gain access, including to privileged accounts.
Fix
Apply the April security rollup or upgrade to Remote Support and Privileged Remote Access 25.3.3 or later, prioritize internet-facing appliances, and review authentication configurations and logs for unauthorized access.

Gitea Docker images trusted a forged header, letting anyone log in as any user

Attackers have started probing a critical flaw in Gitea's official Docker images, the self-hosted Git service used by many development teams. The images shipped a configuration that trusted the X-WEBAUTH-USER header from any source address, so with reverse-proxy login enabled, anyone who could reach the port could send that header and be authenticated as any user, no password required. Tracked as CVE-2026-20896 and rated 9.8, it was fixed in version 1.26.3 late last month, which removes the wildcard and makes reverse-proxy authentication opt-in. Sysdig reported the first exploitation attempt 13 days after disclosure, so far just reconnaissance, against some of the roughly 6,200 internet-facing Gitea instances.

Check
Check whether you run Gitea from its Docker image and on what version, review the app.ini reverse-proxy trusted-proxies setting for a wildcard, and whether the instance is internet-reachable.
Affected
Self-hosted Gitea Docker deployments on version 1.26.2 or earlier with reverse-proxy login enabled (CVE-2026-20896); an unauthenticated attacker who can reach the service can impersonate any user by forging one header.
Fix
Update Gitea to 1.26.3 or later, remove the wildcard from the reverse-proxy trusted-proxies setting, keep management interfaces off the public internet, and review logs for spoofed X-WEBAUTH-USER authentication attempts.

Curl's largest security release fixes 18 flaws, including a 25-year-old bug

The curl project shipped its largest-ever security release, version 8.21.0, fixing 18 vulnerabilities, among them a flaw that had gone unnoticed for 25 years. That bug (CVE-2026-8932) lets an application reuse an existing connection even after its client certificate or key changed, allowing an authentication bypass; it affects software built on the libcurl library rather than the command-line tool. Other fixes address credential confusion, memory-corruption bugs, and improper host validation. Most are rated medium or low, but libcurl is embedded in an enormous range of products, from IoT devices to CI/CD pipelines and cars, so the practical reach is large and easy to overlook.

Check
Identify where curl and especially the libcurl library are used across your applications, devices, containers, and build pipelines, since most exposure comes from embedded libcurl rather than the command-line tool.
Affected
Applications and devices built on libcurl before version 8.21.0 (CVE-2026-8932 and others); those using mutual TLS with changing client certificates face an authentication-bypass risk through connection reuse.
Fix
Update to curl and libcurl 8.21.0, rebuild and redeploy software that bundles libcurl, and prioritize systems using mutual TLS or handling credentials, including embedded and IoT devices that update slowly.

One unpatched Quest KACE box at a Boston MSP exposed 60+ named client organizations - law enforcement, schools, healthcare, and government on one MariaDB dump (CVE-2025-32975)

Quest KACE has a year-old maximum-severity authentication bypass (CVE-2025-32975, CVSS 10.0). Hunt.io researchers now report that an attacker exploited an unpatched KACE appliance at a Boston-area managed services provider called HIQ - then left their entire toolkit on a publicly accessible server with directory listing turned on. The exfiltrated 512 MB MariaDB dump turned out to contain the full appliance-managed endpoint list for over 60 named client organizations spanning law enforcement, government, healthcare, education, and private companies. None of those 60-plus organizations had any KACE relationship of their own - they were just customers of the MSP that ran it unpatched.

Check
Inventory Quest KACE SMA instances reachable from the public internet, check their version against the May 2025 patched build, and review helpdesk tickets and asset records for sensitive material that would surface in a database dump.
Affected
Quest KACE Systems Management Appliance (SMA) instances at or below the pre-May 2025 patched version. CVSS 10.0 unauthenticated SSO impersonation. CISA KEV-listed since April 2026.
Fix
Apply Quest's May 2025 patched version immediately. Remove KACE SMA from direct internet exposure (place behind VPN or firewall), rotate KACE admin credentials, and audit for unauthorized accounts created via runkbot.exe.

Critical MOVEit Automation flaw lets attackers take over file-transfer servers without logging in - Cl0p hit MOVEit's sister product in 2023 and stole data from 62 million people (CVE-2026-4670)

Progress Software released emergency patches Sunday for two MOVEit Automation flaws. The worst, CVE-2026-4670 (CVSS 9.8), lets remote attackers reach the management interface without logging in - and from there take administrative control. Airbus researchers disclosed both flaws privately and Progress hasn't seen exploitation in the wild, but the comparison with MOVEit's history is uncomfortable: the Cl0p ransomware gang exploited MOVEit Transfer in 2023 to steal data from 2,100 organizations and 62 million individuals. Shodan shows 1,400+ MOVEit Automation instances exposed online, including a dozen linked to US local and state government agencies.

Check
Inventory MOVEit Automation instances and check the version under Web Admin > Help > About. Search firewall logs for inbound traffic to the service backend command port.
Affected
MOVEit Automation versions before 2025.1.5, 2025.0.9, and 2024.1.8. CVE-2026-4670 (CVSS 9.8, auth bypass) and CVE-2026-5174 (CVSS 7.7, privilege escalation). 1,400+ internet-exposed instances per Shodan, including state and local government agencies. Internet-reachable management interfaces face acute risk.
Fix
Upgrade to MOVEit Automation 2025.1.5, 2025.0.9, or 2024.1.8 using the full installer (the standard service installer does not patch the flaw). Restrict the management interface to internal networks only. Rotate every credential MOVEit holds for downstream destinations - cloud storage, SFTP servers, partner systems. Block external traffic to the service backend command port at the firewall.

SonicWall patches three SonicOS firewall flaws after CrowdStrike disclosed them - the worst lets attackers reach the management interface without logging in (CVE-2026-0204)

SonicWall released emergency firmware updates for Gen 6, Gen 7, and Gen 8 firewalls after CrowdStrike's research team disclosed three SonicOS flaws on April 29. The worst is CVE-2026-0204 (CVSS 8.0), a weak authentication bug in the management interface that lets an attacker on an adjacent network reach management functions without logging in - and from there change firewall rules, disable security protections, or open new holes. The other two are post-authentication: CVE-2026-0205 is a path traversal that breaks out of restricted directories, and CVE-2026-0206 is a buffer overflow that crashes the firewall. No public exploits yet.

Check
Patch every SonicWall Gen 6, Gen 7, and Gen 8 firewall to the latest firmware today, and confirm no SonicWall management interface or SSL-VPN is reachable from the public internet.
Affected
Gen 6 firewalls (TZ 300/400/500/600, NSA, SM, SOHO) running 6.5.5.1-6n or older. Gen 7 firewalls and NSv (TZ270-TZ670, NSa 2700-6700, NSsp, NSv on ESX/KVM/Hyper-V/AWS/Azure) running 7.0.1-5169 or 7.3.1-7013 or older. Gen 8 (TZ80-TZ680, NSa 2800-5800) running 8.1.0-8017 or older.
Fix
Upgrade to Gen 8 firmware 8.2.0-8009, Gen 7 firmware 7.3.2-7010, or Gen 6 6.5.5.2-28n. Until patched, disable HTTP and HTTPS firewall management on all interfaces, disable SSL-VPN, and restrict management to SSH only from trusted IPs. Take a full configuration backup before upgrading Gen 6 - downgrading from 6.5.5.2-28n deletes all LDAP users and resets MFA.