{"id":"CVE-2026-108981","state":"PUBLISHED","title":"ngx_cache_purge before 3.0.4 can allow file deletion via a symlink attack in certain situations where nginx and a served application (e.g., WordPress) run under the same user accou","description":"ngx_cache_purge before 3.0.4 can allow file deletion via a symlink attack in certain situations where nginx and a served application (e.g., WordPress) run under the same user account. The attacker must be able to create a symlink inside the cache path. Version 3.0.4 fixes this for the case of a symlink created at an arbitrary earlier time, but does not resolve an applicable TOCTOU race condition. (The ngx_cache_purge module follows symlinks while walking the cache directory tree during purge operations. The module relies on nginx's ngx_walk_tree(), which relies on stat() and therefore follows symlinks.)","publishedAt":"2026-10-12T02:27:15.378Z","updatedAt":"2026-10-14T17:18:00.208Z","severity":{"score":3.6,"label":"Low","version":"3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L","source":"mitre"},"assigner":"mitre","products":["denji ngx_cache_purge"],"affected":[{"vendor":"denji","product":"ngx_cache_purge","defaultStatus":"unaffected","versions":[{"version":"2.4.0","status":"affected","lessThanOrEqual":"2.5.6","versionType":"semver"},{"version":"3.0.0","status":"affected","lessThan":"3.0.4","versionType":"semver"}],"modules":["purge_all","partial/wildcard key purge","asynchronous purge queue","vary-aware variant deletion"],"programFiles":["ngx_cache_purge_module.c"],"programRoutines":[{"name":"ngx_http_cache_purge_all"},{"name":"ngx_http_cache_purge_partial"},{"name":"ngx_http_cache_purge_process_queue"},{"name":"ngx_http_cache_purge_delete_variants"}],"repo":"https://github.com/nginx-modules/ngx_cache_purge"}],"references":["https://github.com/nginx-modules/ngx_cache_purge/pull/72","https://github.com/nginx-modules/ngx_cache_purge/commit/a6da1352f52a8a02dd6828e88c39ed42fddcee96","https://github.com/nginx-modules/ngx_cache_purge/releases/tag/3.0.4"],"weaknesses":["CWE-61"],"ingestedAt":"2026-10-29T20:10:33.477Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/108xxx/CVE-2026-108981.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-108981","state":"PUBLISHED","datePublished":"2026-10-12T02:27:15.378Z","dateUpdated":"2026-10-14T17:18:00.208Z","assignerShortName":"mitre","assignerOrgId":"8254265b-2729-46b6-b9e3-3dfca2d5bfca","dateReserved":"2026-10-12T02:27:14.593Z"},"containers":{"cna":{"descriptions":[{"lang":"en","value":"ngx_cache_purge before 3.0.4 can allow file deletion via a symlink attack in certain situations where nginx and a served application (e.g., WordPress) run under the same user account. The attacker must be able to create a symlink inside the cache path. Version 3.0.4 fixes this for the case of a symlink created at an arbitrary earlier time, but does not resolve an applicable TOCTOU race condition. (The ngx_cache_purge module follows symlinks while walking the cache directory tree during purge operations. The module relies on nginx's ngx_walk_tree(), which relies on stat() and therefore follows symlinks.)"}],"affected":[{"vendor":"denji","product":"ngx_cache_purge","defaultStatus":"unaffected","versions":[{"version":"2.4.0","status":"affected","lessThanOrEqual":"2.5.6","versionType":"semver"},{"version":"3.0.0","status":"affected","lessThan":"3.0.4","versionType":"semver"}],"modules":["purge_all","partial/wildcard key purge","asynchronous purge queue","vary-aware variant deletion"],"programFiles":["ngx_cache_purge_module.c"],"programRoutines":[{"name":"ngx_http_cache_purge_all"},{"name":"ngx_http_cache_purge_partial"},{"name":"ngx_http_cache_purge_process_queue"},{"name":"ngx_http_cache_purge_delete_variants"}],"repo":"https://github.com/nginx-modules/ngx_cache_purge"}],"references":[{"url":"https://github.com/nginx-modules/ngx_cache_purge/pull/72","tags":["patch"]},{"url":"https://github.com/nginx-modules/ngx_cache_purge/commit/a6da1352f52a8a02dd6828e88c39ed42fddcee96","tags":["patch"]},{"url":"https://github.com/nginx-modules/ngx_cache_purge/releases/tag/3.0.4"}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"LOCAL","availabilityImpact":"LOW","baseScore":3.6,"baseSeverity":"LOW","confidentialityImpact":"NONE","integrityImpact":"LOW","privilegesRequired":"LOW","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:L","version":"3.1"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-61","description":"CWE-61 UNIX Symbolic Link (Symlink) Following","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"mitre","orgId":"8254265b-2729-46b6-b9e3-3dfca2d5bfca","dateUpdated":"2026-10-12T02:27:15.378Z"},"configurations":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"<code>\n\nnginx built with the ngx_cache_purge module and a proxy, fastcgi, scgi or uwsgi cache path with purge walks in use (purge_all, a wildcard purge, or cache_purge_vary_aware; arbitrary file deletion requires purge_all or a wildcard purge whose key reduces to an empty prefix), and an attacker able to create a symbolic link inside the cache path, for example when nginx and a web application run as the same user. The attacker does not need PURGE access: any legitimate purge of this kind, such as an automatic purge_all issued by a cache plugin, triggers the traversal.\n\n</code>\n\n\n\n<br>"}],"value":"nginx built with the ngx_cache_purge module and a proxy, fastcgi, scgi or uwsgi cache path with purge walks in use (purge_all, a wildcard purge, or cache_purge_vary_aware; arbitrary file deletion requires purge_all or a wildcard purge whose key reduces to an empty prefix), and an attacker able to create a symbolic link inside the cache path, for example when nginx and a web application run as the same user. The attacker does not need PURGE access: any legitimate purge of this kind, such as an automatic purge_all issued by a cache plugin, triggers the traversal."}],"solutions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"Fixed in commit a6da135 (PR #72) on the releases/stable-3.0 branch. 2.4 through 2.5.6 users should upgrade to 3.x, or backport the change to the two ngx_walk_tree() call sites in those versions.\n\n\n\n\n\n<br>"}],"value":"Fixed in commit a6da135 (PR #72) on the releases/stable-3.0 branch. 2.4 through 2.5.6 users should upgrade to 3.x, or backport the change to the two ngx_walk_tree() call sites in those versions."}],"workarounds":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"Restrict write access to the cache directories and all of their parent directories to the nginx user only, and do not run nginx and untrusted application code (for example PHP-FPM) as the same user. Remove any symbolic links found inside configured cache paths (find &lt;cache_path&gt; -type l). These measures also limit the similar traversal in nginx's own cache loader, which the fix in the module does not change.\n\n\n\n\n\n<br>"}],"value":"Restrict write access to the cache directories and all of their parent directories to the nginx user only, and do not run nginx and untrusted application code (for example PHP-FPM) as the same user. Remove any symbolic links found inside configured cache paths (find <cache_path> -type l). These measures also limit the similar traversal in nginx's own cache loader, which the fix in the module does not change."}],"x_generator":{"engine":"CVE-Request-form 0.0.1"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-14T17:17:47.968041Z","id":"CVE-2026-108981","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-14T17:18:00.208Z"}}]}}}