{"cve":{"cve_id":"CVE-2026-47734","is_kev":false,"kev_date_added":null,"kev_vendor_project":null,"kev_product":null,"kev_vulnerability_name":null,"kev_short_description":null,"kev_required_action":null,"kev_due_date":null,"kev_known_ransomware":null,"kev_notes":null,"kev_cwes":null,"epss_score":0.00188,"epss_percentile":0.08492,"epss_as_of":"2026-06-23","description":"Dulwich is a pure-Python implementation of the Git file formats and protocols. Starting in version 0.1.0 and prior to version 1.2.5, a client with push access could push a tiny crafted thin pack (~174 bytes)  whose delta header declares a huge   dest_size. When dulwich ingested it via  add_thin_pack / apply_delta, it would  allocate hundreds of MB of memory based on that attacker-controlled size, with no relationship to the actual bytes received. Operators running a Dulwich-based Git server that exposes git-receive-pack (i.e. accepts pushes) - for example via dulwich.server functionality, the HTTP  smart server, or anything built on ReceivePackHandler - are impacted. The issue is patched in 1.2.5. add_thin_pack now accepts a max_input_size keyword (bytes; 0/None = unlimited, matching git's semantics), and ReceivePackHandler reads receive.maxInputSize from the repository config and passes it through. Wire reads are counted and a PackInputTooLarge exception is raised once the cap is exceeded - equivalent to git index-pack --max-input-size. Users should upgrade to Dulwich 1.2.5 or later and set receive.maxInputSize in their server's repository config to a sane bound for their environment. On unpatched versions, receive.maxInputSize has no effect, so it cannot be used as a workaround. Until upgrading, operators should restrict dulwich-receive-pack (push) access to trusted, authenticated clients only, or disable it entirely on servers that only need to serve fetches and/or run the server under an OS-level memory limit (e.g. ulimit, cgroups/MemoryMax, or a container memory limit) so a malicious push is killed rather than taking down the host.","published_at":"2026-06-10T22:11:02.704000Z","last_modified_at":null,"cvss_v3_score":5.7,"cvss_v3_vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H","cvss_v3_severity":"MEDIUM","cvss_v4_score":null,"cvss_v4_vector":null,"cvss_v4_severity":null,"ssvc_decision":null,"ssvc_exploitation":null,"ssvc_automatable":null,"ssvc_technical_impact":null,"cwes":["CWE-400","CWE-789"],"nvd_references":["https://github.com/jelmer/dulwich/security/advisories/GHSA-xrvj-v92f-53gj","https://github.com/jelmer/dulwich/releases/tag/dulwich-1.2.5"],"vuln_status":null,"trending_score":null,"is_trending":false,"has_trended":false,"trended_number_one":false,"trending_peak_score":null,"trending_peak_rank":null,"started_trending_at":null,"trended_number_one_at":null,"summary_generated":null,"summary_generated_at":null,"summary_model":null,"created_at":"2026-06-24T00:09:39.878444Z","updated_at":"2026-06-28T23:30:41.527238Z"},"effective_severity":"MEDIUM","badges":[],"impact_analysis":[],"cvss_v3_decoded":{"version":"3.1","metrics":[{"metric":"AV","name":"Attack Vector","value":"N","value_label":"Network"},{"metric":"AC","name":"Attack Complexity","value":"L","value_label":"Low"},{"metric":"PR","name":"Privileges Required","value":"L","value_label":"Low"},{"metric":"UI","name":"User Interaction","value":"R","value_label":"Required"},{"metric":"S","name":"Scope","value":"U","value_label":"Unchanged"},{"metric":"C","name":"Confidentiality","value":"N","value_label":"None"},{"metric":"I","name":"Integrity","value":"N","value_label":"None"},{"metric":"A","name":"Availability","value":"H","value_label":"High"}]},"cvss_v4_decoded":{"version":null,"metrics":[]},"affected":[{"vendor_slug":"jelmer","vendor_name":"jelmer","product_slug":"dulwich","product_name":"dulwich","version_start":">= 0.1.0, < 1.2.5","version_start_inclusive":true,"version_end":">= 0.1.0, < 1.2.5","version_end_inclusive":true,"cpe23_uri":"cve5:jelmer:dulwich:>= 0.1.0, < 1.2.5:>= 0.1.0, < 1.2.5"}],"exploit_refs":[],"news":[],"references":[{"url":"https://github.com/jelmer/dulwich/security/advisories/GHSA-xrvj-v92f-53gj","source_type":"VENDOR_ADVISORY","tags":["advisory"]},{"url":"https://github.com/jelmer/dulwich/releases/tag/dulwich-1.2.5","source_type":"PATCH","tags":["patch"]}],"timeline":[{"type":"published","at":"2026-06-10T22:11:02.704000Z","label":"CVE published","source":null},{"type":"cvss_changed","at":"2026-06-28T17:54:57.553414Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:54:57.553414Z","label":"CVSS score revised","source":"cvelistv5"},{"type":"cvss_changed","at":"2026-06-28T17:54:57.553414Z","label":"CVSS score revised","source":"cvelistv5"}]}