{"id":"CVE-2026-48702","summary":"Rekor has an OOM Condition due to Unbounded gzip Decompression in Alpine APK Parsing Logic","details":"Rekor is a software supply chain transparency log. Starting in version 0.3.0 and prior to version 1.5.2, the `Package.Unmarshal()` function in `pkg/types/alpine/apk.go` decompresses the signature and control gzip members of an APK file into in-memory buffers without bounding the total decompressed size. The existing `max_apk_metadata_size` check (default 1MB) is only applied to individual tar entry header sizes after decompression completes, so it does not prevent a decompression bomb from consuming unbounded heap memory. An attacker can craft a gzip stream that compresses at a ~1000:1 ratio (e.g., 2MB compressed zeros → 2GB decompressed). When submitted as spec.package.content in an Alpine `ProposedEntry`, the server decompresses the full payload into memory during request processing, triggering a fatal Go runtime out-of-memory error or OS OOM-kill that cannot be caught by the server's recover() middleware. This is reachable via two unauthenticated endpoints, `POST /api/v1/log/entries (createLogEntry)` and `POST /api/v1/log/entries/retrieve (searchLogQuery)`. Both invoke `V001Entry.Canonicalize()` → `fetchExternalEntities()` → `apk.Unmarshal(packageData)`, which performs the unbounded decompression. Version 1.5.2 patches the issue. There is no effective workaround. Setting `max_request_body_size` reduces but does not eliminate exposure due to the ~1000:1 compression ratio (a 1MB body limit still allows ~1GB heap allocation). Setting `max_apk_metadata_size` has no effect on this vulnerability since the check is applied after decompression.","aliases":["GHSA-47q9-m4ww-924m","GO-2026-5778"],"modified":"2026-08-15T03:54:50.088131113Z","published":"2026-08-13T13:14:19.324Z","related":["openSUSE-SU-2026:11154-1","openSUSE-SU-2026:11398-1","openSUSE-SU-2026:21262-1","openSUSE-SU-2026:21483-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48702.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-770"]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48702.json"},{"type":"ADVISORY","url":"https://github.com/sigstore/rekor/security/advisories/GHSA-47q9-m4ww-924m"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48702"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/sigstore/rekor","events":[{"introduced":"e4303a87b92081e162e080ff69f36830c1035c09"},{"fixed":"3b75cd9c9a101bae26eecf1ad261d94aba247ee9"}],"database_specific":{"source":"AFFECTED_FIELD","extracted_events":[{"introduced":"0.3.0"},{"fixed":"1.5.2"}]}}],"versions":["v1.5.1","v1.5.0","v1.4.3","v1.4.2","v1.4.1","v1.4.0","v1.3.10","v1.3.9","v1.3.8","v1.3.7","v1.3.6","v1.3.5","v1.3.4","v1.3.3","v1.3.2","v1.3.1","v1.3.0","v1.2.2","v1.2.1","v1.2.0","v1.1.1","v1.1.0","v1.0.0","v1.0.0-rc.1","v1.0-rc","v0.12.1","v0.12.0","v0.11.0","v0.10.0","v0.9.1","v0.9.0","v0.8.2","v0.8.1","v0.8.0","v0.7.0","v0.6.0","v0.5.0","v0.4.0","v0.3.0"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-48702.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}