{"answers":{"affected":"1 open source package ship an affected version, including mastodon. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-25540 in the wild and no public exploit code.","fix":"Upgrade mastodon to 4.5.6 or later.","what":"CVE-2026-25540 is a medium-severity vulnerability in mastodon, published on 4 Feb 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-2026-25540 and fix it if it is affected.\n\nWhat it is: CVE-2026-25540 is a medium-severity vulnerability in mastodon, published on 4 Feb 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-2026-25540 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- mastodon (Bitnami): affected all versions; fixed in 4.5.6\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-2026-25540/ (Markdown: https://insights.sbomify.com/CVE-2026-25540/index.md)","id":"CVE-2026-25540","markdown":"https://insights.sbomify.com/CVE-2026-25540/index.md","name":"CVE-2026-25540","record":{"aliases":["BIT-mastodon-2026-25540","GHSA-ccpr-m53r-mfwr"],"analysis":{"component_type":"server_software","fix_type":"upgrade","impacts":["data_read","data_modify"],"network_reachable":"yes","non_default_config":true,"product_category":"Mastodon social network","requires_auth":"none","summary":"Attackers can poison the cache to serve incorrect ActivityPub content, leaking data to blocked users or hiding it from legitimate ones.","user_interaction":"not_required","vuln_class":"information_disclosure"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"mastodon","vendor":"joinmastodon"}],"cvss":{"score":6.5,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L","version":"3.1"},"cwes":[{"id":"CWE-524","name":"Use of Cache Containing Sensitive Information"}],"description":"Mastodon is a free, open-source social network server based on ActivityPub. Prior to versions 4.3.19, 4.4.13, 4.5.6, Mastodon is vulnerable to web cache poisoning via `Rails.cache. When AUTHORIZED_FETCH is enabled, the ActivityPub endpoints for pinned posts and featured hashtags have contents that depend on the account that signed the HTTP request. However, these contents are stored in an internal cache and reused with no regards to the signing actor. As a result, an empty response generated for a blocked user account may be served to requests from legitimate non-blocked actors, or conversely, content intended for non-blocked actors may be returned to blocked actors. This issue has been patched in versions 4.3.19, 4.4.13, 4.5.6.","ecosystems":["Bitnami"],"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":"Information disclosure in mastodon","id":"CVE-2026-25540","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Bitnami","product":null,"products":[],"type":"information_disclosure","year":"2026"},"n_packages":1,"n_references":1,"next":{"headline":"Bytes is vulnerable to integer overflow in BytesMut::reserve","id":"CVE-2026-25541"},"packages":[{"ecosystem":"Bitnami","fixed":["4.5.6"],"introduced":["0"],"last_affected":[],"package":"mastodon","purl":"pkg:bitnami/mastodon","source":"BIT-mastodon-2026-25540"}],"prev":{"headline":"SiYuan has Arbitrary File Write via /api/file/copyFile leading to RCE","id":"CVE-2026-25539"},"products":["mastodon"],"published":"2026-02-04","related":[{"cvss_score":10,"headline":"Mastodon vulnerable to arbitrary file creation through media attachments","id":"CVE-2023-36460","kev_date_added":null,"published":"2023-07-06"},{"cvss_score":9.8,"headline":"Improper Restriction of Excessive Authentication Attempts in mastodon/mastodon","id":"CVE-2022-2166","kev_date_added":null,"published":"2022-11-16"},{"cvss_score":9.8,"headline":"Missing authorization in n/a","id":"CVE-2022-24307","kev_date_added":null,"published":"2022-02-03"},{"cvss_score":9.8,"headline":"Auth bypass in n/a","id":"CVE-2018-21018","kev_date_added":null,"published":"2019-09-22"},{"cvss_score":9.4,"headline":"Mastodon Remote user impersonation and takeover","id":"CVE-2024-23832","kev_date_added":null,"published":"2024-02-01"},{"cvss_score":9.3,"headline":"Mastodon vulnerable to Cross-site Scripting through oEmbed preview cards","id":"CVE-2023-36459","kev_date_added":null,"published":"2023-07-06"},{"cvss_score":8.5,"headline":"Lack of media type verification of Activity Streams objects allows impersonation of remote accounts","id":"CVE-2024-25623","kev_date_added":null,"published":"2024-02-19"}],"sources":[{"class":"attribution","licence":"Apache-2.0","name":"Bitnami","prefix":"BIT"},{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"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":"2026-02-05","vendors":["mastodon"]},"summary":"Attackers can poison the cache to serve incorrect ActivityPub content, leaking data to blocked users or hiding it from legitimate ones.","url":"https://insights.sbomify.com/CVE-2026-25540/"}