{"id":"CVE-2026-115374","kind":"vulnerability","aliases":["CVE-2026-115374"],"related":[],"title":"Incus: S3 server lets presigned URL holders copy other bucket objects","description":"Incus 7.0.0 before 7.0.2 and 7.1.0 before 7.5.0 contains a signature verification flaw in its built-in S3 server that allows presigned URL holders to inject unsigned x-amz-* headers. Attackers can add an unsigned X-Amz-Copy-Source header to a presigned upload URL to copy other bucket objects onto the granted key, disclosing their contents and ETags.","summary":"Incus's built-in S3 server does not verify some x-amz-* headers in presigned URLs, so a holder of a presigned upload URL can add an unsigned X-Amz-Copy-Source header. This copies other objects in the bucket onto the granted key, exposing their contents and ETags.","severity":"high","cvss":7.1,"epss":0.00153,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["incus","infrastructure","object-storage","s3","self-hosted"],"not_affected_if":["default-config","no-s3-server"],"how_to_check":"- Run `incus version` and compare against the affected ranges: 7.0.0 before 7.0.2 and 7.1.0 before 7.5.0.\n- Check whether the built-in S3 server is enabled in the Incus configuration (unknown how to confirm from the sources).","fix":"- Upgrade Incus to `7.0.2` on the 7.0 branch or to `7.5.0` on the 7.1 branch.","status":"open","published_at":"2026-10-22T19:17:43+00:00","first_seen_at":"2026-10-23T21:57:31+00:00","triaged_at":"2026-10-25T03:31:27+00:00","updated_at":"2026-10-25T03:31:27+00:00","category":"infrastructure","confidence":0.7,"triage":{"at":"2026-10-25T03:31:27Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade Incus to `7.0.2` on the 7.0 branch or to `7.5.0` on the 7.1 branch.","reach":"network","title":"Incus: S3 server lets presigned URL holders copy other bucket objects","impact":"medium","summary":"Incus's built-in S3 server does not verify some x-amz-* headers in presigned URLs, so a holder of a presigned upload URL can add an unsigned X-Amz-Copy-Source header. This copies other objects in the bucket onto the granted key, exposing their contents and ETags.","category":"infrastructure","nicknames":[],"who_cares":["incus","self-hosted","s3","object-storage"],"confidence":0.7,"needs_auth":"yes","worst_case":"Attacker reads other bucket objects' contents and ETags via copy","analyst_note":"","how_to_check":"- Run `incus version` and compare against the affected ranges: 7.0.0 before 7.0.2 and 7.1.0 before 7.5.0.\n- Check whether the built-in S3 server is enabled in the Incus configuration (unknown how to confirm from the sources).","needs_analyst":false,"not_affected_if":["default-config","no-s3-server"],"who_is_affected":"Only deployments running Incus 7.0.0 to before 7.0.2 or 7.1.0 to before 7.5.0 that expose the built-in S3 server and issue presigned URLs are exposed. Anyone who holds a presigned upload URL can read other objects in the same bucket. Systems not running the built-in S3 server can skip it.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"high"},"cost_usd":0.00063,"input_tokens":3413,"output_tokens":578,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-115374':14A,17A '-2026':13A,16A '7.0.0':80C '7.0.2':82C '7.1.0':84C '7.5.0':86C 'add':54B,113C 'allow':100C 'amz':40B,59B,109C,118C 'attack':111C 'bucket':10A,69B,130C 'built':30B,95C 'built-in':29B,94C 'contain':87C 'content':76B,138C 'copi':8A,60B,64B,119C,128C 'cve':12A,15A 'disclos':136C 'etag':78B,140C 'expos':74B 'flaw':91C 'grant':72B,134C 'header':41B,62B,110C,121C 'holder':7A,47B,103C 'host':26B 'incus':1A,18B,27B,79C 'infrastructur':19B 'inject':105C 'key':73B,135C 'let':4A 'object':11A,21B,66B,131C 'object-storag':20B 'onto':70B,132C 'presign':5A,43B,50B,101C,124C 's3':2A,23B,32B,97C 'self':25B 'self-host':24B 'server':3A,33B,98C 'signatur':89C 'sourc':61B,120C 'storag':22B 'unsign':56B,106C,115C 'upload':51B,125C 'url':6A,44B,52B,102C,126C 'verif':90C 'verifi':36B 'x':39B,58B,108C,117C 'x-amz':38B,107C 'x-amz-copy-sourc':57B,116C","nicknames":[],"mitigations":[],"who_affected":"Only deployments running Incus 7.0.0 to before 7.0.2 or 7.1.0 to before 7.5.0 that expose the built-in S3 server and issue presigned URLs are exposed. Anyone who holds a presigned upload URL can read other objects in the same bucket. Systems not running the built-in S3 server can skip it.","tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-22T19:17:43+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","cvss_by":"disclosure@vulncheck.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-115374","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-115374","severity":null,"published_at":"2026-10-22T19:17:43+00:00","modified_at":"2026-10-23T17:06:36+00:00","first_seen_at":"2026-10-23T21:57:31+00:00","fetched_at":"2026-10-23T22:29:02+00:00","note":null},{"source":"epss","external_id":"CVE-2026-115374","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-115374","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-24T07:15:51+00:00","fetched_at":"2026-10-24T07:15:51+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}