{"answers":{"affected":"4 open source packages ship an affected version, including org.apache.logging.log4j:log4j-core. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-34479 in the wild and no public exploit code.","fix":"Upgrade org.apache.logging.log4j:log4j-core to 2.25.4 or later.","what":"CVE-2026-34479 is a medium-severity vulnerability in Apache Log4j 1 to Log4j 2 bridge, published on 10 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-34479 and fix it if it is affected.\n\nWhat it is: CVE-2026-34479 is a medium-severity vulnerability in Apache Log4j 1 to Log4j 2 bridge, published on 10 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-34479 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- org.apache.logging.log4j:log4j-core (Maven): affected from 2.7; fixed in 2.25.4\n- org.apache.logging.log4j:log4j-core (Maven): affected from 2.7; fixed in 2.25.4\n- org.apache.logging.log4j:log4j-core (Maven): affected from 3.0.0-beta1 up to 3.0.0-beta2; no fix listed\n- org.apache.logging.log4j:log4j-core (Maven): affected from 3.0.0-beta1 up to 3.0.0-beta2; no fix listed\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-34479/ (Markdown: https://insights.sbomify.com/CVE-2026-34479/index.md)","id":"CVE-2026-34479","markdown":"https://insights.sbomify.com/CVE-2026-34479/index.md","name":"CVE-2026-34479","record":{"aliases":["CLEANSTART-2026-LD36349","CLEANSTART-2026-NL43370","CLEANSTART-2026-RP42469","CLEANSTART-2026-VX38000","CLSA-2026-1779124827","CLSA-2026-1780054786","CLSA-2026-1790941398","DEBIAN-CVE-2026-34479","ECHO-0849-6e0a-d963","GHSA-h383-gmxw-35v2","MINI-22x7-p6vf-g27p","MINI-287m-m9p4-r24r","MINI-2wjj-ghq4-f5hf","MINI-34j6-c8vq-8c95","MINI-35x4-5mwx-2r6x","MINI-394c-3qwp-ggcg","MINI-3hcg-3499-qjxp","MINI-3m82-833v-7wg9","MINI-3w2q-xr78-cxww","MINI-3xxq-9mcg-vfvf","MINI-44m7-m6fv-pc9q","MINI-524w-82ph-qq74","MINI-5p37-6wv7-rgm4","MINI-5xcm-cvv3-r9q5","MINI-69wm-5834-fgrj","MINI-6c4w-hrfp-58w4","MINI-6gg5-wmjx-4rx8","MINI-6hx5-xc42-gg23","MINI-7cv6-g56h-qcmf","MINI-7pf2-584j-v6x3","MINI-7w24-wgpq-mg4j","MINI-8hqc-rmww-jx79","MINI-8mrr-p5g3-vp88","MINI-8pw3-26m5-v8vj","MINI-8r4q-wqwx-gv68","MINI-8x5g-9mch-wvxq","MINI-922j-3cr3-pr7p","MINI-933j-mhch-jh57","MINI-9392-jgff-9rh4","MINI-9c6x-jvxh-jwcv","MINI-9hq3-rxxr-g8jr","MINI-9wm4-3658-vfw5","MINI-cfx8-3mg3-jvx3","MINI-cj25-w84h-9f6g","MINI-g9wv-j9xm-3prr","MINI-gcf3-86w5-7v2x","MINI-ggm8-9xcm-g485","MINI-h452-vjm7-2r5w","MINI-h74h-6jm2-q83v","MINI-hgf4-5fv4-63m7","MINI-hw79-m453-qqmj","MINI-j3vr-hwcr-x86q","MINI-j6hh-g2gf-72x3","MINI-j9g6-54pp-88f9","MINI-jfmc-6jmv-3fxf","MINI-jrg2-r4q8-6wfj","MINI-m5pv-56mj-x754","MINI-m849-g4f5-6996","MINI-mmx9-952w-3f6f","MINI-mv6c-47x7-fmhm","MINI-p63m-wm6r-h6p3","MINI-p99h-9wpv-4444","MINI-pc5c-wj3g-cgvw","MINI-pcvw-rq5m-9gw2","MINI-pjp5-w7p2-79h2","MINI-q4vp-58w9-8fg7","MINI-qrp6-rp44-qx9p","MINI-rj98-7jg3-hm6q","MINI-rr4q-mw43-3qv8","MINI-rvff-2fxj-fg4w","MINI-rvqf-8fvc-fc82","MINI-v8rm-34f2-fc9v","MINI-wpw6-28vq-55x6","MINI-xv5m-fjc9-wp7p","ROOT-APP-MAVEN-CVE-2026-34479","UBUNTU-CVE-2026-34479"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Java logging library","requires_auth":"none","summary":"Attackers can cause log data loss by injecting forbidden XML characters, disrupting downstream log processing systems.","user_interaction":"not_required","vuln_class":"other"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"apache","cpe":[{"product":"log4j","vendor":"apache"}],"cvss":{"score":6.9,"severity":"medium","source":"cna","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N","version":"4.0"},"cwes":[{"id":"CWE-116","name":"Improper Encoding or Escaping of Output"}],"description":"The Log4j1XmlLayout from the Apache Log4j 1-to-Log4j 2 bridge fails to escape characters forbidden by the XML 1.0 standard, producing malformed XML output. Conforming XML parsers are required to reject documents containing such characters with a fatal error, which may cause downstream log processing systems to drop or fail to index affected records.\n\nTwo groups of users are affected:\n\n  *  Those using Log4j1XmlLayout directly in a Log4j Core 2 configuration file.\n  *  Those using the Log4j 1 configuration compatibility layer with org.apache.log4j.xml.XMLLayout specified as the layout class.\n\nUsers are advised to upgrade to Apache Log4j 1-to-Log4j 2 bridge version 2.25.4, which corrects this issue.\n\nNote: The Apache Log4j 1-to-Log4j 2 bridge is deprecated and will not be present in Log4j 3. Users are encouraged to consult the  Log4j 1 to Log4j 2 migration guide https://logging.apache.org/log4j/2.x/migrate-from-log4j1.html , and specifically the section on eliminating reliance on the bridge.","ecosystems":["Maven"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"Apache Log4j 1 to Log4j 2 bridge: silent log event loss in Log4j1XmlLayout due to unescaped XML 1.0 forbidden characters","id":"CVE-2026-34479","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Maven","product":null,"products":[],"type":"other","year":"2026"},"n_packages":4,"n_references":5,"next":{"headline":"Apache Log4j Core: Silent log event loss in XmlLayout due to unescaped XML 1.0 forbidden characters","id":"CVE-2026-34480"},"packages":[{"ecosystem":"Maven","fixed":["2.25.4"],"introduced":["2.7"],"last_affected":[],"package":"org.apache.logging.log4j:log4j-core","purl":null,"source":"GHSA-h383-gmxw-35v2"},{"ecosystem":"Maven","fixed":["2.25.4"],"introduced":["2.7"],"last_affected":[],"package":"org.apache.logging.log4j:log4j-core","purl":"pkg:maven/org.apache.logging.log4j/log4j-core","source":"GHSA-h383-gmxw-35v2"},{"ecosystem":"Maven","fixed":[],"introduced":["3.0.0-beta1"],"last_affected":["3.0.0-beta2"],"package":"org.apache.logging.log4j:log4j-core","purl":null,"source":"GHSA-h383-gmxw-35v2"},{"ecosystem":"Maven","fixed":[],"introduced":["3.0.0-beta1"],"last_affected":["3.0.0-beta2"],"package":"org.apache.logging.log4j:log4j-core","purl":"pkg:maven/org.apache.logging.log4j/log4j-core","source":"GHSA-h383-gmxw-35v2"}],"prev":{"headline":"Apache Log4j Core: Log injection in Rfc5424Layout due to silent configuration incompatibility","id":"CVE-2026-34478"},"products":["Apache Log4j 1 to Log4j 2 bridge"],"published":"2026-04-10","related":[{"cvss_score":10,"headline":"Apache Log4j2 Remote Code Execution","id":"CVE-2021-44228","kev_date_added":"2021-12-10","published":"2021-12-10"},{"cvss_score":9,"headline":"Apache Log4j2 Deserialization of Untrusted Data","id":"CVE-2021-45046","kev_date_added":"2023-05-01","published":"2021-12-14"},{"cvss_score":9.8,"headline":"SQL injection in JDBC Appender in Apache Log4j V1","id":"CVE-2022-23305","kev_date_added":null,"published":"2022-01-18"},{"cvss_score":9.8,"headline":"Deserialization of Untrusted Data in Log4j","id":"CVE-2017-5645","kev_date_added":null,"published":"2017-04-17"},{"cvss_score":8.8,"headline":"Deserialization of untrusted data in JMSSink in Apache Log4j 1.x","id":"CVE-2022-23302","kev_date_added":null,"published":"2022-01-18"},{"cvss_score":7.5,"headline":"Apache Log4j 1.x (EOL) allows DoS in Chainsaw and SocketAppender","id":"CVE-2023-26464","kev_date_added":null,"published":"2023-03-10"},{"cvss_score":7.5,"headline":"Deserialization of untrusted data in JMSAppender in Apache Log4j 1.2","id":"CVE-2021-4104","kev_date_added":null,"published":"2021-12-14"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"yes","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-04-10","vendors":["Apache Software Foundation"]},"summary":"Attackers can cause log data loss by injecting forbidden XML characters, disrupting downstream log processing systems.","url":"https://insights.sbomify.com/CVE-2026-34479/"}