Cloudflare Fixes ACME Validation Bug Allowing WAF Bypass to Origin Servers

Cloudflare has addressed a security vulnerability impacting its Automatic Certificate Management Environment ACME validation logic that made it possible to bypass security controls and access origin servers. "The vulnerability was rooted in how our edge network processed requests destined for the...

CVE-2025-62291

In the eap-mschapv2 plugin client-side in strongSwan before 6.0.3, a malicious EAP-MSCHAPv2 server can send a crafted message of size 6 through 8, and cause an integer underflow that potentially results in a heap-based buffer overflow...

CVE-2025-62291

In the eap-mschapv2 plugin client-side in strongSwan before 6.0.3, a malicious EAP-MSCHAPv2 server can send a crafted message of size 6 through 8, and cause an integer underflow that potentially results in a heap-based buffer overflow...

Unity Linux 20.1050e / 20.1060e / 20.1070e Security Update: kernel (UTSA-2026-001037)

The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2026-001037 advisory. net/ipv4/tcpinput.c in the Linux kernel before 4.7 does not properly determine the rate of challenge ACK segments, which makes it easier for remote attackers to hija...

Allocation of Resources Without Limits or Throttling

Overview Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling via the ACME TLS certificates' automatic generation. An attacker can exhaust system resources by opening multiple connections, sending minimal ClientHello messages with acme-tls/1, an...

GHSA-CWJM-3F7H-9HWQ Traefik's ACME TLS-ALPN fast path lacks timeouts and close on handshake stall

Impact There is a potential vulnerability in Traefik ACME TLS certificates' automatic generation: the ACME TLS-ALPN fast path can allow unauthenticated clients to tie up goroutines and file descriptors indefinitely when the ACME TLS challenge is enabled. A malicious client can open many...

Unity Linux 20.1060a / 20.1070a Security Update: kernel (UTSA-2026-003058)

The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2026-003058 advisory. net/ipv4/tcpinput.c in the Linux kernel before 4.7 does not properly determine the rate of challenge ACK segments, which makes it easier for remote attackers to hija...

Unity Linux 20.1060e / 20.1070e Security Update: kernel (UTSA-2026-003431)

The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2026-003431 advisory. net/ipv4/tcpinput.c in the Linux kernel before 4.7 does not properly determine the rate of challenge ACK segments, which makes it easier for remote attackers to hija...

Cryptographic Semantic Binding Flaw

ALTCHA libraries are vulnerable to a cryptographic semantic binding flaw. The vulnerability is due to ambiguous HMAC binding between challenge parameters and the nonce, which allows an attacker to splice or reinterpret a valid proof-of-work submission for example by modifying the expiration value...

CVE-2023-49944

The Challenge Response feature of BeyondTrust Privilege Management for Windows PMfW before 2023-07-14 allows local administrators to bypass this feature by decrypting the shared key, or by locating the decrypted shared key in process memory. The threat is mitigated by the Agent Protection feature...

CVE-2021-41467

Cross-site scripting XSS vulnerability in application/controllers/dropbox.php in JustWriting 1.0.0 and below allow remote attackers to inject arbitrary web script or HTML via the challenge parameter...

CVE-2022-26943

The Motorola MTM5000 series firmwares generate TETRA authentication challenges using a PRNG using a tick count register as its sole entropy source. Low boottime entropy and limited re-seeding of the pool renders the authentication challenge vulnerable to two attacks. First, due to the limited...

Unified Framework for Qualifying Security Boundary of PUFs against Machine Learning Attacks

Physical Unclonable Functions PUFs serve as lightweight, hardware-intrinsic entropy sources widely deployed in IoT security applications. However, delay-based PUFs are vulnerable to Machine Learning Attacks MLAs, undermining their assumed unclonability. There are no valid metrics for evaluating P...

CVE-1999-0391

The cryptographic challenge of SMB authentication in Windows 95 and Windows 98 can be reused, allowing an attacker to replay the response and impersonate a user...

SUSE CVE-2025-68113

ALTCHA is privacy-first software for captcha and bot protection. A cryptographic semantic binding flaw in ALTCHA libraries allows challenge payload splicing, which may enable replay attacks. The HMAC signature does not unambiguously bind challenge parameters to the nonce, allowing an attacker to...

PT-2025-53609

Name of the Vulnerable Software and Affected Versions FreshRSS versions prior to 1.28.0 Description FreshRSS utilizes weak random number generators mt rand and uniqid for creating remember-me authentication tokens and challenge-response nonces. This allows attackers to predict valid session token...

CVE-2025-62004

BullWall Server Intrusion Protection services are initialized after login services. An authenticated attacker with administrative permissions can log in after boot and bypass MFA. SIP service does not retroactively enforce the challenge or disconnect unauthenticated sessions. Versions 4.6.0.0,...

PT-2025-52342

Name of the Vulnerable Software and Affected Versions BullWall versions 4.6.0.0 through 4.6.1.4 Description BullWall Server Intrusion Protection services start after login services. An attacker who is already authenticated and has administrative privileges can log in following a system boot,...

CVE-2025-68113

ALTCHA is privacy-first software for captcha and bot protection. A cryptographic semantic binding flaw in ALTCHA libraries allows challenge payload splicing, which may enable replay attacks. The HMAC signature does not unambiguously bind challenge parameters to the nonce, allowing an attacker to...

GO-2025-4239 ALTCHA Proof-of-Work Vulnerable to Challenge Splicing and Replay in github.com/altcha-org/altcha-lib-go

ALTCHA Proof-of-Work Vulnerable to Challenge Splicing and Replay in github.com/altcha-org/altcha-lib-go...