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Another Apache Log4j Vulnerability Is Actively Exploited in the Wild (CVE-2021

Apache Log4j 2 RCE CVE-2021-44228 is actively exploited via crafted JNDI lookups; Palo Alto Unit 42 urges upgrading to Log4j 2.17.1.

Unit 42 details CVE-2021-44228, an easily exploited remote code execution flaw in Apache Log4j 2 where attacker-supplied JNDI lookups in logged user input cause payload download and execution. Massive internet-wide scanning for unpatched systems has begun, with observed follow-on activity including information stealing, Cobalt Strike delivery, and coinmining. The recommended fix is Log4j 2.17.1, which also patches CVE-2021-45046, CVE-2021-45105, and CVE-2021-44832. Widely used Java software including Apache Struts, Solr, Druid, Flink, ElasticSearch, and Spring Boot is affected.

Palo Alto Unit 42 · 29d agoExploit / PoC in the wildCVE-2021-44228CVE-2021-45046CVE-2021-45105+3 CVEs

CVE-2022-22965: Spring Core Remote Code Execution Vulnerability Exploited In the Wild (SpringShell) (Updated)

Attackers actively exploit Spring Framework RCE CVE-2022-22965 (SpringShell, CVSS 9.8) to deploy webshells; patches 5.3.18/5.2.20 shipped March 31, 2022.

CVE-2022-22965 enables unauthenticated remote code execution in the widely used Spring Framework (CVSS 9.8), which Unit 42 has observed being exploited in the wild. The flaw stems from getCachedIntrospectionResults exposing the class object during parameter binding, letting attackers manipulate the class loader to modify Tomcat logging and upload a JSP webshell. Public PoCs require JDK 9+, Tomcat, WAR packaging, and spring-webmvc or spring-webflux dependencies on Spring 5.3.0-5.3.17, 5.2.0-5.2.19, or older. Fixes shipped in Spring Framework 5.3.18 and 5.2.20; the related Spring Cloud Function flaw CVE-2022-22963 was patched March 29, 2022.

CVE-2026-34486: Apache Tomcat EncryptInterceptor Fail-Open Bypass

Technical analysis shows CVE-2026-34486 is a one-line fail-open regression in Tomcat Tribes enabling unauthenticated RCE via Java deserialization.

CVE-2026-34486 is a fail-open regression in Tomcat's Tribes EncryptInterceptor, introduced while fixing the CVE-2026-29146 padding-oracle flaw; Apache rated it Important and NVD scores it 7.5 High. Decryption failures are now forwarded to an unfiltered ObjectInputStream, and public PoC repositories demonstrate unauthenticated RCE on default port 4000 when clustering, the EncryptInterceptor, a reachable receiver and deserialization gadgets are all present. Affected releases 9.0.116, 10.1.53 and 11.0.20 are fixed in 9.0.117, 10.1.54 and 11.0.21; Tomcat 8.5 is unaffected.

Hackers Are Probing PaperCut Servers, and 47% Still Have No Patch

PaperCut pre-auth RCE CVE-2026-81578 actively exploited; 47% of tracked installs unpatched and exposed to remote code execution.

Huntress confirmed active exploitation of a pre-authentication RCE flaw in PaperCut (CVE-2026-81578), chainable with CVE-2026-82078 to achieve SYSTEM-level code execution via PaperCut's Application Server. Observed attacks focused on short reconnaissance (whoami, ver, tasklist) with no persistence, but a malicious Java class dropping into the installation directory leaves the jdbc:derby:memory:pwn breadcrumb. Roughly 47% of ~2,500 tracked installations run version 23 or earlier with no patch yet available.

Security Affairs · 10d agoExploit / PoC in the wildCVE-2026-81578CVE-2026-82078

CVE-2026-81578 + CVE-2026-82078 | PaperCut NG/MF Authentication Bypass and Unsafe Dynamic Class Loading Vulnerabilities

Two chained PaperCut NG/MF flaws, CVE-2026-81578 and CVE-2026-82078, enable pre-auth RCE, with active exploitation confirmed in customer environments.

PaperCut NG/MF is affected by CVE-2026-81578, an improper access control flaw (CVSS 4.0 8.8) allowing unauthenticated configuration changes, and CVE-2026-82078, an unsafe dynamic class loading flaw (CVSS 4.0 9.4) enabling arbitrary Java bytecode execution. Chained, they yield pre-authentication remote code execution on the PaperCut Application Server. PaperCut confirmed active exploitation and customer incidents, and Huntress observed exploitation starting August 26, 2026. Emergency Patch Release 2 is available for NG/MF v24-v26, with IOCs including suspicious pc-app.exe child processes, truncated server.log files, and AnyDesk installs.

Horizon3.ai · 14d agoExploit / PoC in the wildCVE-2026-81578CVE-2026-820781